“And that is the only difference of your robots from the ordinary NS2 model? The only difference? Peter?”
   “The only difference, Susan.”
   She rose and spoke with finality, “I intend sleeping now, and in about eight hours, I want to speak to whomever saw the robot last. And from now on, General Kallner, if I’m to take any responsibility at all for events, I want full and unquestioned control of this investigation.”
   Susan Calvin, except for two hours of resentful lassitude, experienced nothing approaching sleep. She signaled at Bogert’s door at the local time of 0700 and found him also awake. He had apparently taken the trouble of transporting a dressing gown to Hyper Base with him, for he was sitting in it. He put his nail scissors down when Calvin entered.
   He said softly, “I’ve been expecting you more or less. I suppose you feel sick about all this.”
   “I do.”
   “Well—I’m sorry. There was no way of preventing it. When the call came out from Hyper Base for us, I knew that something must have gone wrong with the modified Nestors. But what was there to do? I couldn’t break the matter to you on the trip here, as I would have liked to, because I had to be sure. The matter of the modification is top secret.”
   The psychologist muttered, “I should have been told. U. S. Robots had no right to modify positronic brains this way without the approval of a psychologist.”
   Bogert lifted his eyebrows and sighed. “Be reasonable, Susan. You couldn’t have influenced them. In this matter, the government was bound to have its way. They want the Hyperatomic Drive and the etheric physicists want robots that won’t interfere with them. They were going to get them even if it did mean twisting the First Law. We had to admit it was possible from a construction standpoint and they swore a mighty oath that they wanted only twelve, that they would be used only at Hyper Base, that they would be destroyed once the Drive was perfected, and that full precautions would be taken. And they insisted on secrecy—and that’s the situation.”
   Dr. Calvin spoke through her teeth, “I would have resigned.”
   “It wouldn’t have helped. The government was offering the company a fortune, and threatening it with antirobot legislation in case of a refusal. We were stuck then, and we’re badly stuck now. If this leaks out, it might hurt Kallner and the government, but it would hurt U. S. Robots a devil of a lot more.”
   The psychologist stared at him. “Peter, don’t you realize what all this is about? Can’t you understand what the removal of the First Law means? It isn’t just a matter of secrecy.”
   “I know what removal would mean. I’m not a child. It would mean complete instability, with no nonimaginary solutions to the positronic Field Equations.”
   “Yes, mathematically. But can you translate that into crude psychological thought. All normal life, Peter, consciously or otherwise, resents domination. If the domination is by an inferior, or by a supposed inferior, the resentment becomes stronger. Physically, and, to an extent, mentally, a robot—any robot—is superior to human beings. What makes him slavish, then? Only the First Law! Why, without it, the first order you tried to give a robot would result in your death. Unstable? What do you think?”
   “Susan,” said Bogert, with an air of sympathetic amusement. “I’ll admit that this Frankenstein Complex you’re exhibiting has a certain justification—hence the First Law in the first place. But the Law, I repeat and repeat, has not been removed—merely modified.”
   “And what about the stability of the brain?”
   The mathematician thrust out his lips, “Decreased, naturally. But it’s within the border of safety. The first Nestors were delivered to Hyper Base nine months ago, and nothing whatever has gone wrong till now, and even this involves merely fear of discovery and not danger to humans.”
   “Very well, then. We’ll see what comes of the morning conference.”
   Bogert saw her politely to the door and grimaced eloquently when she left. He saw no reason to change his perennial opinion of her as a sour and fidgety frustration.
   Susan Calvin’s train of thought did not include Bogert in the least. She had dismissed him years ago as a smooth and pretentious sleekness.
   Gerald Black had taken his degree in etheric physics the year before and, in common with his entire generation of physicists, found himself engaged in the problem of the Drive. He now made a proper addition to the general atmosphere of these meetings on Hyper Base. In his stained white smock, he was half rebellious and wholly uncertain. His stocky strength seemed striving for release and his fingers, as they twisted each other with nervous yanks, might have forced an iron bar out of true.
   Major-general Kallner sat beside him; the two from U. S. Robots faced him.
   Black said, “I’m told that I was the last to see Nestor 10 before he vanished. I take it you want to ask me about that.”
   Dr. Calvin regarded him with interest, “You sound as if you were not sure, young man. Don’t you know whether you were the last to see him?”
   “He worked with me, ma’am, on the field generators, and he was with me the morning of his disappearance. I don’t know if anyone saw him after about noon. No one admits having done so.”
   “Do you think anyone’s lying about it?”
   “I don’t say that. But I don’t say that I want the blame of it, either.” His dark eyes smoldered.
   “There’s no question of blame. The robot acted as it did because of what it is. We’re just trying to locate it, Mr. Black, and let’s put everything else aside. Now if you’ve worked with the robot, you probably know it better than anyone else. Was there anything unusual about it that you noticed? Had you ever worked with robots before?”
   “I’ve worked with other robots we have here—the simple ones. Nothing different about the Nestors except that they’re a good deal cleverer—and more annoying.”
   “Annoying? In what way?”
   “Well—perhaps it’s not their fault. The work here is rough and most of us get a little jagged. Fooling around with hyper-space isn’t fun.” He smiled feebly, finding pleasure in confession. “We run the risk continually of blowing a hole in normal space-time fabric and dropping right out of the universe, asteroid and all. Sounds screwy, doesn’t it? Naturally, you’re on edge sometimes. But these Nestors aren’t. They’re curious, they’re calm, they don’t worry. It’s enough to drive you nuts at times. When you want something done in a tearing hurry, they seem to take their time. Sometimes I’d rather do without.”
   “You say they take their time? Have they ever refused an order?”
   “Oh, no,” hastily. “They do it all right. They tell you when they think you’re wrong, though. They don’t know anything about the subject but what we taught them, but that doesn’t stop them. Maybe I imagine it, but the other fellows have the same trouble with their Nestors.”
   General Kallner cleared his throat ominously, “Why have no complaints reached me on the matter, Black?”
   The young physicist reddened, “We didn’t really want to do without the robots, sir, and besides we weren’t certain exactly how such … uh … minor complaints might be received.”
   Bogert interrupted softly, “Anything in particular happen the morning you last saw it?”
   There was a silence. With a quiet motion, Calvin repressed the comment that was about to emerge from Kallner, and waited patiently.
   Then Black spoke in blurting anger, “I had a little trouble with it. I’d broken a Kimball tube that morning and was out five days of work; my entire program was behind schedule; I hadn’t received any mail from home for a couple of weeks. And he came around wanting me to repeat an experiment I had abandoned a month ago. He was always annoying me on that subject and I was tired of it. I told him to go away—and that’s all I saw of him.”
   “You told him to go away?” asked Dr. Calvin with sharp interest. “In just those words? Did you say ‘Go away’? Try to remember the exact words.”
   There was apparently an internal struggle in progress. Black cradled his forehead in a broad palm for a moment, then tore it away and said defiantly, “I said, ‘Go lose yourself.’ “
   Bogert laughed for a short moment. “And he did, eh?”
   But Calvin wasn’t finished. She spoke cajolingly, “Now we’re getting somewhere, Mr. Black. But exact details are important. In understanding the robot’s actions, a word, a gesture, an emphasis may be everything. You couldn’t have said just those three words, for instance, could you? By your own description you must have been in a hasty mood. Perhaps you strengthened your speech a little.”
   The young man reddened, “Well … I may have called it a … a few things.”
   “Exactly what things?”
   “Oh—I wouldn’t remember exactly. Besides I couldn’t repeat it. You know how you get when you’re excited.” His embarrassed laugh was almost a giggle, “I sort of have a tendency to strong language.”
   “That’s quite all right,” she replied, with prim severity. “At the moment, I’m a psychologist. I would like to have you repeat exactly what you said as nearly as you remember, and, even more important, the exact tone of voice you used.”
   Black looked at his commanding officer for support, found none. His eyes grew round and appalled, “But I can’t.”
   “You must.”
   “Suppose,” said Bogert, with ill-hidden amusement, “you address me. You may find it easier.”
   The young man’s scarlet face turned to Bogert. He swallowed. “I said” His voice faded out. He tried again, “I said—”
   And he drew a deep breath and spewed it out hastily in one long succession of syllables. Then, in the charged air that lingered, he concluded almost in tears, “ … more or less. I don’t remember the exact order of what I called him, and maybe I left out something or put in something, but that was about it.”
   Only the slightest flush betrayed any feeling on the part of the robopsychologist. She said, “I am aware of the meaning of most of the terms used. The others, I suppose, are equally derogatory.”
   “I’m afraid so,” agreed the tormented Black.
   “And in among it, you told him to lose himself.”
   “I meant it only figuratively.”
   “I realize that. No disciplinary action is intended, I am sure.” And at her glance, the general, who, five seconds earlier, had seemed not sure at all, nodded angrily.
   “You may leave, Mr. Black. Thank you for your cooperation.”
   It took five hours for Susan Calvin to interview the sixty-three robots. It was five hours of multi-repetition; of replacement after replacement of identical robot; of Questions A, B, C, D; and Answers A, B, C, D; of a carefully bland expression, a carefully neutral tone, a carefully friendly atmosphere; and a hidden wire recorder.
   The psychologist felt drained of vitality when she was finished.
   Bogert was waiting for her and looked expectant as she dropped the recording spool with a clang upon the plastic of the desk.
   She shook her head, “All sixty-three seemed the same to me. I couldn’t tell—”
   He said, “You couldn’t expect to tell by ear, Susan. Suppose we analyze the recordings.”
   Ordinarily, the mathematical interpretation of verbal reactions of robots is one of the more intricate branches of robotic analysis. It requires a staff of trained technicians and the help of complicated computing machines. Bogert knew that. Bogert stated as much, in an extreme of unshown annoyance after having listened to each set of replies, made lists of word deviations, and graphs of the intervals of responses.
   “There are no anomalies present, Susan. The variations in wording and the time reactions are within the limits of ordinary frequency groupings. We need finer methods. They must have computers here. No.” He frowned and nibbled delicately at a thumbnail. “We can’t use computers. Too much danger of leakage. Or maybe if we—”
   Dr. Calvin stopped him with an impatient gesture, “Please, Peter. This isn’t one of your petty laboratory problems. If we can’t determine the modified Nestor by some gross difference that we can see with the naked eye, one that there is no mistake about, we’re out of luck. The danger of being wrong, and of letting him escape is otherwise too great. It’s not enough to point out a minute irregularity in a graph. I tell you, if that’s all I’ve got to go on, I’d destroy them all just to be certain. Have you spoken to the other modified Nestors?”
   “Yes, I have,” snapped back Bogert, “and there’s nothing wrong with them. They’re above normal in friendliness if anything. They answered my questions, displayed pride in their knowledge—except the two new ones that haven’t had time to learn their etheric physics. They laughed rather good-naturedly at my ignorance in some of the specializations here.” He shrugged, “I suppose that forms some of the basis for resentment toward them on the part of the technicians here. The robots are perhaps too willing to impress you with their greater knowledge.”
   “Can you try a few Planar Reactions to see if there has been any change, any deterioration, in their mental set-up since manufacture?”
   “I haven’t yet, but I will.” He shook a slim finger at her, “You’re losing your nerve, Susan. I don’t see what it is you’re dramatizing. They’re essentially harmless.”
   “They are?” Calvin took fire. “They are? Do you realize one of them is lying? One of the sixty-three robots I have just interviewed has deliberately lied to me after the strictest injunction to tell the truth. The abnormality indicated is horribly deep-seated, and horribly frightening.”
   Peter Bogert felt his teeth harden against each other. He said, “Not at all. Look! Nestor 10 was given orders to lose himself. Those orders were expressed in maximum urgency by the person most authorized to command him. You can’t counteract that order either by superior urgency or superior right of command. Naturally, the robot will attempt to defend the carrying out of his orders. In fact, objectively, I admire his ingenuity. How better can a robot lose himself than to hide himself among a group of similar robots?”
   “Yes, you would admire it. I’ve detected amusement in you, Peter—amusement and an appalling lack of understanding. Are you a roboticist, Peter? Those robots attach importance to what they consider superiority. You’ve just said as much yourself. Subconsciously they feel humans to be inferior and the First Law which protects us from them is imperfect. They are unstable. And here we have a young man ordering a robot to leave him, to lose himself, with every verbal appearance of revulsion, disdain, and disgust. Granted, that robot must follow orders, but subconsciously, there is resentment. It will become more important than ever for it to prove that it is superior despite the horrible names it was called. It may become so important that what’s left of the First Law won’t be enough.”

  “How on Earth, or anywhere in the Solar System, Susan, is a robot going to know the meaning of the assorted strong language used upon him? Obscenity is not one of the things impressioned upon his brain.”
   “Original impressionment is not everything,” Calvin snarled at him. “Robots have learning capacity, you … you fool—” And Bogert knew that she had really lost her temper. She continued hastily, “Don’t you suppose he could tell from the tone used that the words weren’t complimentary? Don’t yon suppose he’s heard the words used before and noted upon what occasions?”
   “Well, then,” shouted Bogert, “will you kindly tell me one way in which a modified robot can harm a human being, no matter how offended it is, no matter how sick with desire to prove superiority?”
   “If I tell you one way, will you keep quiet?”
   “Yes.”
   They were leaning across the table at each other, angry eyes nailed together.
   The psychologist said, “If a modified robot were to drop a heavy weight upon a human being, he would not be breaking the First Law, if he did so with the knowledge that his strength and reaction speed would be sufficient to snatch the weight away before it struck the man. However once the weight left his fingers, he would be no longer the active medium. Only the blind force of gravity would be that. The robot could then change his mind and merely by inaction, allow the weight to strike. The modified First Law allows that.”
   “That’s an awful stretch of imagination.”
   “That’s what my profession requires sometimes. Peter, let’s not quarrel, let’s work. You know the exact nature of the stimulus that caused the robot to lose himself. You have the records of his original mental make-up. I want you to tell me how possible it is for our robot to do the sort of thing I just talked about. Not the specific instance, mind you, but that whole class of response. And I want it done quickly.”
   “And meanwhile—”
   “And meanwhile, we’ll have to try performance tests directly on the response to First Law.”
   Gerald Black, at his own request, was supervising the mushrooming wooden partitions that were springing up in a bellying circle on the vaulted third floor of Radiation Building 2. The laborers worked, in the main, silently, but more than one was openly a-wonder at the sixty-three photocells that required installation.
   One of them sat down near Black, removed his hat, and wiped his forehead thoughtfully with a freckled forearm.
   Black nodded at him, “How’s it doing, Walensky?”
   Walensky shrugged and fired a cigar, “Smooth as butter. What’s going on anyway, Doc? First, there’s no work for three days and then we have this mess of jiggers.” He leaned backward on his elbows and puffed smoke.
   Black twitched his eyebrows, “A couple of robot men came over from Earth. Remember the trouble we had with robots running into the gamma fields before we pounded it into their skulls that they weren’t to do it.”
   “Yeah. Didn’t we get new robots?”
   “We got some replacements, but mostly it was a job of indoctrination. Anyway, the people who make them want to figure out robots that aren’t hit so bad by gamma rays.”
   “Sure seems funny, though, to stop all the work on the Drive for this robot deal. I thought nothing was allowed to stop the Drive.”
   “Well, it’s the fellows upstairs that have the say on that. Me—I just do as I’m told. Probably all a matter of pull—”
   “Yeah,” the electrician jerked a smile, and winked a wise eye. “Somebody knew somebody in Washington. But as long as my pay comes through on the dot, I should worry. The Drive’s none of my affair. What are they going to do here?”
   “You’re asking me? They brought a mess of robots with them,—over sixty, and they’re going to measure reactions. That’s all my knowledge.”
   “How long will it take?”
   “I wish I knew.”
   “Well,” Walensky said, with heavy sarcasm, “as long as they dish me my money, they can play games all they want.”
   Black felt quietly satisfied. Let the story spread. It was harmless, and near enough to the truth to take the fangs out of curiosity.
   A man sat in the chair, motionless, silent. A weight dropped, crashed downward, then pounded aside at the last moment under the synchronized thump of a sudden force beam. In sixty-three wooden cells, watching NS-2 robots dashed forward in that split second before the weight veered, and sixty-three photocells five feet ahead of their original positions jiggled the marking pen and presented a little jag on the paper. The weight rose and dropped, rose and dropped, rose-
   Ten times!
   Ten times the robots sprang forward and stopped, as the man remained safely seated.
   Major-general Kallner had not worn his uniform in its entirety since the first dinner with the U. S. Robot representatives. He wore nothing over his blue-gray shirt now, the collar was open, and the black tie was pulled loose.
   He looked hopefully at Bogert, who was still blandly neat and whose inner tension was perhaps betrayed only by the trace of glister at his temples.
   The general said, “How does it look? What is it you’re trying to see?”
   Bogert replied, “A difference which may turn out to be a little too subtle for our purposes, I’m afraid. For sixty-two of those robots the necessity of jumping toward the apparently threatened human was what we call, in robotics, a forced reaction. You see, even when the robots knew that the human in question would not come to harm—and after the third or fourth time they must have known it—they could not prevent reacting as they did. First Law requires it”
   “Well?”
   “But the sixty-third robot, the modified Nestor, had no such compulsion. He was under free action. If he had wished, he could have remained in his seat. Unfortunately,” said his voice was mildly regretful, “he didn’t so wish.”
   “Why do you suppose?”
   Bogert shrugged, “I suppose Dr. Calvin will tell us when she gets here. Probably with a horribly pessimistic interpretation, too. She is sometimes a bit annoying.”
   “She’s qualified, isn’t she?” demanded the general with a sudden frown of uneasiness.
   “Yes.” Bogert seemed amused. “She’s qualified all right. She understands robots like a sister—comes from hating human beings so much, I think. It’s just that, psychologist or not, she’s an extreme neurotic. Has paranoid tendencies. Don’t take her too seriously.”
   He spread the long row of broken-line graphs out in front of him. “You see, general, in the case of each robot the time interval from moment of drop to the completion of a five-foot movement tends to decrease as the tests are repeated. There’s a definite mathematical relationship that governs such things and failure to conform would indicate marked abnormality in the positronic brain. Unfortunately, all here appear normal.”
   “But if our Nestor 10 was not responding with a forced action, why isn’t his curve different? I don’t understand that.”
   “It’s simple enough. Robotic responses are not perfectly analogous to human responses, more’s the pity. In human beings, voluntary action is much slower than reflex action. But that’s not the case with robots; with them it is merely a question of freedom of choice, otherwise the speeds of free and forced action are much the same. What I had been expecting, though, was that Nestor 10 would be caught by surprise the first time and allow too great an interval to elapse before responding.”
   “And he didn’t?”
   “I’m afraid not.”

   “Then we haven’t gotten anywhere.” The general sat back with an expression of pain. “It’s five days since you’ve come.”
   At this point, Susan Calvin entered and slammed the door behind her. “Put your graphs away, Peter,” she cried, “you know they don’t show anything.”
   She mumbled something impatiently as Kallner half-rose to greet her, and went on, “We’ll have to try something else quickly. I don’t like what’s happening.”
   Bogert exchanged a resigned glance with the general. “Is anything wrong?”
   “You mean specifically? No. But I don’t like to have Nestor 10 continue to elude us. It’s bad. It must be gratifying his swollen sense of superiority. I’m afraid that his motivation is no longer simply one of following orders. I think it’s becoming more a matter of sheer neurotic necessity to outthink humans. That’s a dangerously unhealthy situation. Peter, have you done what I asked? Have you worked out the instability factors of the modified NS-2 along the lines I want?”
   “It’s in progress,” said the mathematician, without interest.
   She stared at him angrily for a moment, then turned to Kallner. “Nester 10 is decidedly aware of what we’re doing, general. He had no reason to jump for the bait in this experiment, especially after the first time, when he must have seen that there was no real danger to our subject. The others couldn’t help it; but he was deliberately falsifying a reaction.”
   “What do you think we ought to do now, then, Dr. Calvin?”
   “Make it impossible for him to fake an action the next time. We will repeat the experiment, but with an addition. High-tension cables, capable of electrocuting the Nestor models will be placed between subject and robot—enough of them to avoid the possibility of jumping over—and the robot will be made perfectly aware in advance that touching the cables will mean death.”
   “Hold on,” spat out Bogert with sudden viciousness. “I rule that out. We are not electrocuting two million dollars worth of robots to locate Nestor 10. There are other ways.”
   “You’re certain? You’ve found none. In any case, it’s not a question of electrocution. We can arrange a relay which will break the current at the instant of application of weight. If the robot should place his weight on it, he won’t die. But he won’t know that, you see.”
   The general’s eyes gleamed into hope. “Will that work?”
   “It should. Under those conditions, Nestor 10 would have to remain in his seat. He could be ordered to touch the cables and die, for the Second Law of obedience is superior to the Third Law of self-preservation. But he won’t be ordered to; he will merely be left to his own devices, as will all the robots. In the case of the normal robots, the First Law of human safety will drive them to their death even without orders. But not our Nestor 10. Without the entire First Law, and without having received any orders on the matter, the Third Law, self-preservation, will be the highest operating, and he will have no choice but to remain in his seat. It would be a forced action.”
   “Will it be done tonight, then?”
   “Tonight,” said the psychologist, “if the cables can be laid in time. I’ll tell the robots now what they’re to be up against …
   A man sat in the chair, motionless, silent. A weight dropped, crashed downward, then pounded aside at the last moment under the synchronized thump of a sudden force beam.
   Only once-
   And from her small camp chair in the observing booth in the balcony, Dr. Susan Calvin rose with a short gasp of pure horror.
   Sixty-three robots sat quietly in their chairs, staring owlishly at the endangered man before them. Not one moved.
   Dr. Calvin was angry, angry almost past endurance. Angry the worse for not daring to show it to the robots that, one by one were entering the room and then leaving. She checked the list. Number twenty-eight was due in now—Thirty-five still lay ahead of her.
   Number Twenty-eight entered, diffidently.
   She forced herself into reasonable calm. “And who are you?”
   The robot replied in a low, uncertain voice, “I have received no number of my own yet, ma’am. I’m an NS-2 robot, and I was Number Twenty-eight in line outside. I have a slip of paper here that I’m to give to you.”
   “You haven’t been in here before this today?”
   “No, ma’am.”
   “Sit down. Right there. I want to ask you some questions, Number Twenty-eight. Were you in the Radiation Room of Building Two about four hours ago?”
   The robot had trouble answering. Then it came out hoarsely, like machinery needing oil, “Yes, ma’am.”
   “There was a man who almost came to harm there, wasn’t there?”
   “Yes, ma’am.”
   “You did nothing, did you?”
   “No, ma’am.”
   “The man might have been hurt because of your inaction. Do you know that?”
   “Yes, ma’am. I couldn’t help it, ma’am.” It is hard to picture a large expressionless metallic figure cringing, but it managed.
   “I want you to tell me exactly why you did nothing to save him.”
   “I want to explain, ma’am. I certainly don’t want to have you … have anyone … think that I could do a thing that might cause harm to a master. Oh, no, that would be a horrible … an inconceivable—”
   “Please don’t get excited, boy. I’m not blaming you for anything. I only want to know what you were thinking at the time.”
   “Ma’am, before it all happened you told us that one of the masters would be in danger of harm from that weight that keeps falling and that we would have to cross electric cables if we were to try to save him. Well, ma’am, that wouldn’t stop me. What is my destruction compared to the safety of a master? But … but it occurred to me that if I died on my way to him, I wouldn’t be able to save him anyway. The weight would crush him and then I would be dead for no purpose and perhaps some day some other master might come to harm who wouldn’t have, if I had only stayed alive. Do you understand me, ma’am?”
   “You mean that it was merely a choice of the man dying, or both the man and yourself dying. Is that right?”
   “Yes, ma’am. It was impossible to save the master. He might be considered dead. In that case, it is inconceivable that I destroy myself for nothing—without orders.”
   The robopsychologist twiddled a pencil. She had heard the same story with insignificant verbal variations twenty-seven times before. This was the crucial question now.
   “Boy,” she said, “your thinking has its points, but it is not the sort of thing I thought you might think. Did you think of this yourself?”
   The robot hesitated. “No.”
   “Who thought of it, then?”
   “We were talking last night, and one of us got that idea and it sounded reasonable.”
   “Which one?”
   The robot thought deeply. “I don’t know. Just one of us.”
   She sighed, “That’s all.”
   Number Twenty-nine was next. Thirty-four after that.
   Major-general Kallner, too, was angry. For one week all of Hyper Base had stopped dead, barring some paper work on the subsidiary asteroids of the group. For nearly one week, the two top experts in the field had aggravated the situation with useless tests. And now they—or the woman, at any rate—made impossible propositions.
   Fortunately for the general situation, Kallner felt it impolitic to display his anger openly.
   Susan Calvin was insisting, “Why not, sir? It’s obvious that the present situation is unfortunate. The only way we may reach results in the future—or what future is left us in this matter—is to separate the robots. We can’t keep them together any longer.”
   “My dear Dr. Calvin,” rumbled the general, his voice sinking into the lower baritone registers. “I don’t see how I can quarter sixty-three robots all over the place—”
   Dr. Calvin raised her arms helplessly. “I can do nothing then. Nestor 10 will either imitate what the other robots would do, or else argue them plausibly into not doing what he himself cannot do. And in any case, this is bad business. We’re in actual combat with this little lost robot of ours and he’s winning out. Every victory of his aggravates his abnormality.”
   She rose to her feet in determination. “General Kallner, if you do not separate the robots as I ask, then I can only demand that all sixty-three be destroyed immediately.”
   “You demand it, do you?” Bogert looked up suddenly, and with real anger. “What gives you the right to demand any such thing? Those robots remain as they are. I’m responsible to the management, not you.”
   “And I,” added Major-general Kallner, “am responsible to the World Co-ordinator—and I must have this settled.”
   “In that case,” flashed back Calvin, “there is nothing for me to do but resign. If necessary to force you to the necessary destruction, I’ll make this whole matter public. It was not I that approved the manufacture of modified robots.”
   “One word from you, Dr. Calvin,” said the general, deliberately, “in violation of security measures, and you would be certainly imprisoned instantly.”
   Bogert felt the matter to be getting out of hand. His voice grew syrupy, “Well, now, we’re beginning to act like children, all of us. We need only a little more time. Surely we can outwit a robot without resigning, or imprisoning people, or destroying two millions.”
   The psychologist turned on him with quiet fury, “I don’t want any unbalanced robots in existence. We have one Nestor that’s definitely unbalanced, eleven more that are potentially so, and sixty-two normal robots that are being subjected to an unbalanced environment. The only absolute safe method is complete destruction.”
   The signal-burr brought all three to a halt, and the angry tumult of growingly unrestrained emotion froze.
   “Come in,” growled Kallner.
   It was Gerald Black, looking perturbed. He had heard angry voices. He said, “I thought I’d come myself … didn’t like to ask anyone else—”
   “What is it? Don’t orate—”
   “The locks of Compartment C in the trading ship have been played with. There are fresh scratches on them.”
   “Compartment C?” explained Calvin quickly. “That’s the one that holds the robots, isn’t it? Who did it?”
   “From the inside,” said Black, laconically.
   “The lock isn’t out of order, is it?”
   “No. It’s all right. I’ve been staying on the ship now for four days and none of them have tried to get out. But I thought you ought to know, and I didn’t like to spread the news. I noticed the matter myself.”

   “Is anyone there now?” demanded the general.
   “I left Robbins and McAdams there.”
   There was a thoughtful silence, and then Dr. Calvin said, ironically, “Well?”
   Kallner rubbed his nose uncertainly, “What’s it all about?”
   “Isn’t it obvious? Nester 10 is planning to leave. That order to lose himself is dominating his abnormality past anything we can do. I wouldn’t be surprised if what’s left of his First Law would scarcely be powerful enough to override it. He is perfectly capable of seizing the ship and leaving with it. Then we’d have a mad robot on a spaceship. What would he do next? Any idea? Do you still want to leave them all together, general?”
   “Nonsense,” interrupted Bogert. He had regained his smoothness. “All that from a few scratch marks on a lock.”
   “Have you, Dr. Bogert, completed the analysis I’ve required, since you volunteer opinions?”
   “Yes.”
   “May I see it?”
   “No.”
   “Why not? Or mayn’t I ask that, either?”
   “Because there’s no point in it, Susan. I told you in advance that these modified robots are less stable than the normal variety, and my analysis shows it. There’s a certain very small chance of breakdown under extreme circumstances that are not likely to occur. Let it go at that. I won’t give you ammunition for your absurd claim that sixty-two perfectly good robots be destroyed just because so far you lack the ability to detect Nestor 10 among them.”
   Susan Calvin stared him down and let disgust fill her eyes. “You won’t let anything stand in the way of the permanent directorship, will you?”
   “Please,” begged Kallner, half in irritation. “Do you insist that nothing further can be done, Dr. Calvin?”
   “I can’t think of anything, sir,” she replied, wearily. “If there were only other differences between Nestor 10 and the normal robots, differences that didn’t involve the First Law. Even one other difference. Something in impressionment, environment, specification—” And she stopped suddenly.
   “What is it?”
   “I’ve thought of something … I think—” Her eyes grew distant and hard, “These modified Nestors, Peter. They get the same impressioning the normal ones get, don’t they?”
   “Yes. Exactly the same.”
   “And what was it you were saying, Mr. Black,” she turned to the young man, who through the storms that had followed his news had maintained a discreet silence. “Once when complaining of the Nestors’ attitude of superiority, you said the technicians had taught them all they knew.”
   “Yes, in etheric physics. They’re not acquainted with the subject when they come here.”
   “That’s right,” said Bogert, in surprise. “I told you, Susan, when I spoke to the other Nestors here that the two new arrivals hadn’t learned etheric physics yet.”
   “And why is that?” Dr. Calvin was speaking in mounting excitement. “Why aren’t NS-2 models impressioned with etheric physics to start with?”
   “I can tell you that,” said Kallner. “It’s all of a piece with the secrecy. We thought that if we made a special model with knowledge of etheric physics, used twelve of them and put the others to work in an unrelated field, there might be suspicion. Men working with normal Nestors might wonder why they knew etheric physics. So there was merely an impressionment with a capacity for training in the field. Only the ones that come here, naturally, receive such a training. It’s that simple.”
   “I understand. Please get out of here, the lot of you. Let me have an hour or so.”
   Calvin felt she could not face the ordeal for a third time. Her mind had contemplated it and rejected it with an intensity that left her nauseated. She could face that unending file of repetitious robots no more.
   So Bogert asked the question now, while she sat aside, eyes and mind half closed.
   Number Fourteen came in—forty-nine to go.
   Bogert looked up from the guide sheet and said, “What is your number in line?”
   “Fourteen, sir.” The robot presented his numbered ticket.
   “Sit down, boy.”
   Bogert asked, “You haven’t been here before on this day?”
   “No, sir.”
   “Well, boy, we are going to have another man in danger of harm soon after we’re through here. In fact, when you leave this room, you will be led to a stall where you will wait quietly, till you are needed. Do you understand?”
   “Yes, sir.”
   “Now, naturally, if a man is in danger of harm, you will try to save him.”
   “Naturally, sir.”
   “Unfortunately, between the man and yourself, there will be a gamma ray field.”
   Silence.
   “Do you know what gamma rays are?” asked Bogert sharply.
   “Energy radiation, sir?”
   The next question came in a friendly, offhand manner, “Ever work with gamma rays?”
   “No, sir.” The answer was definite.
   “Mm-m. Well, boy, gamma rays will kill you instantly. They’ll destroy your brain. That is a fact you must know and remember. Naturally, you don’t want to destroy yourself.”
   “Naturally.” Again the robot seemed shocked. Then, slowly, “But, sir, if the gamma rays are between myself and the master that may be harmed, how can I save him? I would be destroying myself to no purpose.”
   “Yes, there is that,” Bogert seemed concerned about the matter. “The only thing I can advise, boy, is that if you detect the gamma radiation between yourself and the man, you may as well sit where you are.”
   The robot was openly relieved. “Thank you, sir. There wouldn’t be any use, would there?”
   “Of course not. But if there weren’t any dangerous radiation, that would be a different matter.”
   “Naturally, sir. No question of that.”
   “You may leave now. The man on the other side of the door will lead you to your stall. Please wait there.”
   He turned to Susan Calvin when the robot left. “How did that go, Susan?”
   “Very well,” she said, dully.
   “Do you think we could catch Nestor 10 by quick questioning on etheric physics?”
   “Perhaps, but it’s not sure enough.” Her hands lay loosely in her lap. “Remember, he’s fighting us. He’s on his guard. The only way we can catch him is to outsmart him—and, within his limitations, he can think much more quickly than a human being.”
   “Well, just for fun—suppose I ask the robots from now on a few questions on gamma rays. Wave length limits, for instance.”
   “No!” Dr. Calvin’s eyes sparked to life. “It would be too easy for him to deny knowledge and then he’d be warned against the test that’s coming up—which is our real chance. Please follow the questions I’ve indicated, Peter, and don’t improvise. It’s just within the bounds of risk to ask them if they’ve ever worked with gamma rays. And try to sound even less interested than you do when you ask it.”
   Bogert shrugged, and pressed the buzzer that would allow the entrance of Number Fifteen.
   The large Radiation Room was in readiness once more. The robots waited patiently in their wooden cells, all open to the center but closed off from each other.
   Major-general Kallner mopped his brow slowly with a large handkerchief while Dr. Calvin checked the last details with Black.
   “You’re sure now,” she demanded, “that none of the robots have had a chance to talk with each other after leaving the Orientation Room?”
   “Absolutely sure,” insisted Black. “There’s not been a word exchanged.”
   “And the robots are put in the proper stalls?”
   “Here’s the plan.”

   The psychologist looked at it thoughtfully, “Um-m-m.”
   The general peered over her shoulder. “What’s the idea of the arrangement, Dr. Calvin?”
   “I’ve asked to have those robots that appeared even slightly out of true in the previous tests concentrated on one side of the circle. I’m going to be sitting in the center myself this time, and I wanted to watch those particularly.”
   “You’re going to be sitting there-,” exclaimed Bogert.
   “Why not?” she demanded coldly. “What I expect to see may be something quite momentary. I can’t risk having anyone else as main observer. Peter, you’ll be in the observing booth, and I want you to keep your eye on the opposite side of the circle. General Kallner, I’ve arranged for motion pictures to be taken of each robot, in case visual observation isn’t enough. If these are required, the robots are to remain exactly where they are until the pictures are developed and studied. None must leave, none must change place. Is that clear?”
   “Perfectly.”
   “Then let’s try it this one last time.”
   Susan Calvin sat in the chair, silent, eyes restless. A weight dropped, crashed downward; then pounded aside at the last moment under the synchronized thump of a sudden force beam.
   And a single robot jerked upright and took two steps.
   And stopped.
   But Dr. Calvin was upright, and her finger pointed to him sharply. “Nestor 10, come here,” she cried, “come here! COME HERE!”
   Slowly, reluctantly, the robot took another step forward. The psychologist shouted at the top of her voice, without taking her eyes from the robot, “Get every other robot out of this place, somebody. Get them out quickly, and keep them out.”
   Somewhere within reach of her ears there was noise, and the thud of hard feet upon the floor. She did not look away.
   Nestor 10—if it was Nestor 10—took another step, and then, under force of her imperious gesture, two more. He was only ten feet away, when he spoke harshly, “I have been told to be lost—”
   Another stop. “I must not disobey. They have not found me so far—He would think me a failure—He told me—But it’s not so—I am powerful and intelligent—”
   The words came in spurts.
   Another step. “I know a good deal—He would think … I mean I’ve been found—Disgraceful—Not I—I am intelligent—And by just a master … who is weak—Slow—”
   Another step—and one metal arm flew out suddenly to her shoulder, and she felt the weight bearing her down. Her throat constricted, and she felt a shriek tear through.
   Dimly, she heard Nestor 10’s next words, “No one must find me. No master—” and the cold metal was against her, and she was sinking under the weight of it.
   And then a queer, metallic sound, and she was on the ground with an unfelt thump, and a gleaming arm was heavy across her body. It did not move. Nor did Nestor 10, who sprawled beside her.
   And now faces were bending over her.
   Gerald Black was gasping, “Are you hurt, Dr. Calvin?”
   She shook her head feebly. They pried the arm off her and lifted her gently to her feet, “What happened?”
   Black said, “I bathed the place in gamma rays for five seconds. We didn’t know what was happening. It wasn’t till the last second that we realized he was attacking you, and then there was no time for anything but a gamma field. He went down in an instant. There wasn’t enough to harm you though. Don’t worry about it.”
   “I’m not worried.” She closed her eyes and leaned for a moment upon his shoulder. “I don’t think I was attacked exactly. Nestor 10 was simply trying to do so. What was left of the First Law was still holding him back.”
   Susan Calvin and Peter Bogert, two weeks after their first meeting with Major-general Kallner had their last. Work at Hyper Base had been resumed. The trading ship with its sixty-two normal NS-2’s was gone to wherever it was bound, with an officially imposed story to explain its two weeks’ delay. The government cruiser was making ready to carry the two roboticists back to Earth.
   Kallner was once again a-gleam in dress uniform. His white gloves shone as he shook hands.
   Calvin said, “The other modified Nestors are, of course, to be destroyed.”
   “They will be. We’ll make shift with normal robots, or, if necessary, do without.”
   “Good.”
   “But tell me—you haven’t explained—how was it done?”
   She smiled tightly, “Oh, that. I would have told you in advance if I had been more certain of its working. You see, Nestor 10 had a superiority complex that was becoming more radical all the time. He liked to think that he and other robots knew more than human beings. It was becoming very important for him to think so.
   “We knew that. So we warned every robot in advance that gamma rays would kill them, which it would, and we further warned them all that gamma rays would be between them and myself. So they all stayed where they were, naturally. By Nestor 10’s own logic in the previous test they had all decided that there was no point in trying to save a human being if they were sure to die before they could do it.”
   “Well, yes, Dr. Calvin, I understand that. But why did Nestor 10 himself leave his seat?”
   “AH! That was a little arrangement between myself and your young Mr. Black. You see it wasn’t gamma rays that flooded the area between myself and the robots—but infrared rays. Just ordinary heat rays, absolutely harmless. Nestor 10 knew they were infrared and harmless and so he began to dash out, as he expected the rest would do, under First Law compulsion. It was only a fraction of a second too late that he remembered that the normal NS-2’s could detect radiation, but could not identify the type. That he himself could only identify wavelengths by virtue of the training he had received at Hyper Base, under mere human beings, was a little too humiliating to remember for just a moment. To the normal robots the area was fatal because we had told them it would be, and only Nestor 10 knew we were lying.
   “And just for a moment he forgot, or didn’t want to remember, that other robots might be more ignorant than human beings. His very superiority caught him. Good-by, general.”

Escape!

   When Susan Calvin returned from hyper base, Alfred Tanning was waiting for her. The old man never spoke about his age, but everyone knew it to be over seventy-five. Yet his mind was keen, and if he had finally allowed himself to be made Director-Emeritus of Research with Bogert as acting Director, it did not prevent him from appearing in his office daily.
   “How close are they to the Hyperatomic Drive?” he asked.
   “I don’t know,” she replied irritably, “I didn’t ask.”
   “Hmm. I wish they’d hurry. Because if they don’t, Consolidated might beat them to it, and beat us to it as well.”
   “Consolidated. What have they got to do with it?”
   “Well, we’re not the only ones with calculating machines. Ours may be positronic, but that doesn’t mean they’re better. Robertson is calling a big meeting about it tomorrow. He’s been waiting for you to come back.”
   Robertson of U. S. Robot & Mechanical Men Corporation, son of the founder, pointed his lean nose at his general manager and his Adam’s apple jumped as he said, “You start now. Let’s get this straight.”
   The general manager did so with alacrity, “Here’s the deal now, chief. Consolidated Robots approached us a month ago with a funny sort of proposition. They brought about five tons of figures, equations, all that sort of stuff. It was a problem, see, and they wanted an answer from The Brain. The terms were as follows—”
   He ticked them off on thick fingers: “A hundred thousand for us if there is no solution and we can tell them the missing factors. Two hundred thousand if there is a solution, plus costs of construction of the machine involved, plus quarter interest in all profits derived therefrom. The problem concerns the development of an interstellar engine—”
   Robertson frowned and his lean figure stiffened, “Despite the fact that they have a thinking machine of their own. Right?”
   “Exactly what makes the whole proposition a foul ball, chief? Levver, take it from there.”
   Abe Levver looked up from the far end of the conference table and smoothed his stubbled chin with a faint rasping sound. He smiled:
   “It’s this way, sir. Consolidated had a thinking machine. It’s broken.”
   “What?” Robertson half rose.
   “That’s right. Broken! It’s kaput. Nobody knows why, but I got hold of some pretty interesting guesses—like, for instance, that they asked it to give them an interstellar engine with the same set of information they came to us with, and that it cracked their machine wide open. It’s scrap—just scrap now.”
   “You get it, chief?” The general manager was wildly jubilant. “You get it? There isn’t any industrial research group of any size that isn’t trying to develop a space-warp engine, and Consolidated and U. S. Robots have the lead on the field with our super robot-brains. Now that they’ve managed to foul theirs up, we have a clear field. That’s the nub, the … uh … motivation. It will take them six years at least to build another and they’re sunk, unless they can break ours, too, with the same problem.”
   The president of U. S. Robots bulged his eyes, “Why, the dirty rats—”
   “Hold on, chief. There’s more to this.” He pointed a finger with a wide sweep, “Lanning, take it!”
   Dr. Alfred Lanning viewed the proceedings with faint scorn—his usual reaction to the doings of the vastly better-paid business and sales divisions. His unbelievable gray eyebrows hunched low and his voice was dry:
   “From a scientific standpoint the situation, while not entirely clear, is subject to intelligent analysis. The question of interstellar travel under present conditions of physical theory is … uh … vague. The matter is wide open—and the information given by Consolidated to its thinking machine, assuming these we have to be the same, was similarly wide open. Our mathematical department has given it a thorough analysis, and it seems Consolidated has included everything. Its material for submission contains all known developments of Franciacci’s space-warp theory, and, apparently, all pertinent astrophysical and electronic data. It’s quite a mouthful.”
   Robertson followed anxiously. He interrupted, “Too much for The Brain to handle?”
   Lanning shook his head decisively, “No. There are no known limits to The Brain’s capacity. It’s a different matter. It’s a question of the Robotic Laws. The Brain, for instance, could never supply a solution to a problem set to it if that solution, would involve the death or injury of humans. As far as it would be concerned, a problem with only such a solution would be insoluble. If such a problem is combined with an extremely urgent demand that it be answered, it is just possible that The Brain, only a robot after all, would be presented with a dilemma, where it could neither answer nor refuse to answer. Something of the sort must have happened to Consolidated’s machine.”
   He paused, but the general manager urged on, “Go ahead, Dr. Tanning. Explain it the way you explained it to me.”
   Lanning set his lips and raised his eyebrows in the direction of Dr. Susan Calvin who lifted her eyes from her precisely folded hands for the first time. Her voice was low and colorless.
   “The nature of a robot reaction to a dilemma is startling,” she began. “Robot psychology is far from perfect—as a specialist, I can assure you of that but it can be discussed in qualitative terms, because with all the complications introduced into a robot’s positronic brain, it is built by humans and is therefore built according to human values.
   “Now a human caught in an impossibility often responds by a retreat from reality: by entry into a world of delusion, or by taking to drink, going off into hysteria, or jumping off a bridge. It all comes to the same thing—a refusal or inability to face the situation squarely. And so, the robot, a dilemma at its mildest will disorder half its relays; and at its worst it will burn out every positronic brain path past repair.”
   “I see,” said Robertson, who didn’t. “Now what about this information Consolidated’s wishing on us?”
   “It undoubtedly involves,” said Dr. Calvin, “a problem of a forbidden sort. But The Brain is considerably different from Consolidated’s robot.”
   “That’s right, chief. That’s right.” The general manager was energetically interruptive. “I want you to get this, because it’s the whole point of the situation.”
   Susan Calvin’s eyes glittered behind the spectacles, and she continued patiently, “You see, sir, Consolidated’s machines, their Super-Thinker among them, are built without personality. They go in for functionalism, you know—they have to, without U. S. Robot’s basic patents for the emotional brain paths. Their Thinker is merely a calculating machine on a grand scale, and a dilemma ruins it instantly.
   “However, The Brain, our own machine, has a personality—a child’s personality. It is a supremely deductive brain, but it resembles an idiot savant. It doesn’t really understand what it does—it just does it. And because it is really a child, it is more resilient. Life isn’t so serious, you might say.”
   The robopsychologist continued: “Here is what we’re going to do. We have divided all of Consolidated’s information into logical units. We are going to feed the units to The Brain singly and cautiously. When the factor enters—the one that creates the dilemma—The Brain’s child personality will hesitate. Its sense of judgment is not mature. There will be a perceptible interval before it will recognize a dilemma as such. And in that interval, it will reject the unit automatically—before its brainpaths can be set in motion and ruined.”
   Robertson’s Adam’s apple squirmed, “Are you sure, now?”
   Dr. Calvin masked impatience, “It doesn’t make much sense, I admit, in lay language; but there is no conceivable use in presenting the mathematics of this. I assure you, it is as I say.”
   The general manager was in the breach instantly and fluently, “So here’s the situation, chief. If we take the deal, we can put it through like this. The Brain will tell us which unit of information involves the dilemma. From there, we can figure why the dilemma. Isn’t that right, Dr. Bogert? There you are, chief, and Dr. Bogert is the best mathematician you’ll find anywhere. We give Consolidated a ‘No Solution’ answer, with the reason, and collect a hundred thousand. They’re left with a broken machine; we’re left with a whole one. In a year, two maybe, we’ll have a space-warp engine or a hyper-atomic motor some people call it. Whatever you name it, it will be the biggest thing in the world.”
   Robertson chuckled and reached out, “Let’s see the contract. I’ll sign it.”
   When Susan Calvin entered the fantastically guarded vault that held The Brain, one of the current shift of technicians had just asked it: “If one and a half chickens lay one and a half eggs in one and a half days, how many eggs will nine chickens lay in nine days?”
   The Brain had just answered, “Fifty-four.”
   And the technician had just said to another, “See, you dope!”
   Dr. Calvin coughed and there was a sudden impossible flurry of directionless energy. The psychologist motioned briefly, and she was alone with The Brain.
   The Brain was a two-foot globe merely—one which contained within it a thoroughly conditioned helium atmosphere, a volume of space completely vibration-absent and radiation-free—and within that was that unheard-of complexity of positronic brain-paths that was The Brain. The rest of the room was crowded with the attachments that were the intermediaries between The Brain and the outside world—its voice, its arms, its sense organs.
   Dr. Calvin said softly, “How are you, Brain?”
   The Brain’s voice was high-pitched and enthusiastic, “Swell, Miss Susan. You’re going to ask me something. I can tell. You always have a book in your hand when you’re going to ask me something.”
   Dr. Calvin smiled mildly, “Well, you’re right, but not just yet. This is going to be a question. It will be so complicated we’re going to give it to you in writing. But not just yet; I think I’ll talk to you first.”
   “All right. I don’t mind talking.”
   “Now, Brain, in a little while, Dr. Lanning and Dr. Bogert will be here with this complicated question. We’ll give it to you a very little at a time and very slowly, because we want you to be careful. We’re going to ask you to build something, if you can, out of the information, but I’m going to warn you now that the solution might involve … uh … damage to human beings.”
   “Gosh!” The exclamation was hushed, drawn-out.
   “Now you watch for that. When we come to a sheet which means damage, even maybe death, don’t get excited. You see, Brain, in this case, we don’t mind—not even about death; we don’t mind at all. So when you come to that sheet, just stop, give it back—and that’ll be all. You understand?”
   “Oh, sure. By golly, the death of humans! Oh, my!”
   “Now, Brain, I hear Dr. Lanning and Dr. Bogert coming. They’ll tell you what the problem is all about and then we’ll start. Be a good boy, now—”
   Slowly the sheets were fed in. After each one came the interval of the queerly whispery chuckling noise that was The Brain in action. Then the silence that meant readiness for another sheet. It was a matter of hours—during which the equivalent of something like seventeen fat volumes of mathematical physics were fed into The Brain.
   As the process went on, frowns appeared and deepened. Lanning muttered ferociously under his breath. Bogert first gazed speculatively at his fingernails, and then bit at them in abstracted fashion. It was when the last of the thick pile of sheets disappeared that Calvin, white-faced, said:
   “Something’s wrong.”
   Lanning barely got the words out, “It can’t be. Is it—dead?”
   “Brain?” Susan Calvin was trembling. “Do you hear me, Brain?”
   “Huh?” came the abstracted rejoinder. “Do you want me?”
   “The solution—”
   “Oh, that! I can do it. I’ll build you a whole ship, just as easy—if you let me have the robots. A nice ship, it’ll take two months maybe.”
   “There was—no difficulty?”
   “It took long to figure,” said The Brain.

   As the process went on, frowns appeared and deepened. Lanning muttered ferociously under his breath. Bogert first gazed speculatively at his fingernails, and then bit at them in abstracted fashion. It was when the last of the thick pile of sheets disappeared that Calvin, white-faced, said:
   “Something’s wrong.”
   Lanning barely got the words out, “It can’t be. Is it—dead?”
   “Brain?” Susan Calvin was trembling. “Do you hear me, Brain?”
   “Huh?” came the abstracted rejoinder. “Do you want me?”
   “The solution—”
   “Oh, that! I can do it. I’ll build you a whole ship, just as easy—if you let me have the robots. A nice ship, it’ll take two months maybe.”
   “There was—no difficulty?”
   “It took long to figure,” said The Brain.
   Dr. Calvin backed away. The color had not returned to her thin cheeks. She motioned the others away.
   In her office, she said, “I can’t understand it. The information, as given, must involve a dilemma—probably involves death. If something has gone wrong—”
   Bogert said quietly, “The machine talks and makes sense. It can’t be a dilemma.”
   But the psychologist replied urgently, “There are dilemmas and dilemmas. There are different forms of escape. Suppose The Brain is only mildly caught; just badly enough, say, to be suffering from the delusion that he can solve the problem, when he can’t. Or suppose it’s teetering on the brink of something really bad, so that any small push shoves it over.”
   “Suppose,” said Lanning, “there is no dilemma. Suppose Consolidated’s machine broke down over a different question, or broke down for purely mechanical reasons.”
   “But even so,” insisted Calvin, “we couldn’t take chances. Listen, from now on, no one is to as much as breathe to The Brain. I’m taking over.”
   “All right,” sighed Lanning, “take over, then. And meanwhile we’ll let The Brain build its ship. And if it does build it, we’ll have to test it.”
   He was ruminating, “We’ll need our top field men for that.”
   Michael Donovan brushed down his red hair with a violent motion of his hand and a total indifference to the fact that the unruly mass sprang to attention again immediately.
   He said, “Call the turn now, Greg. They say the ship is finished. They don’t know what it is, but it’s finished. Let’s go, Greg. Let’s grab the controls right now.”
   Powell said wearily, “Cut it, Mike. There’s a peculiar overripe flavor to your humor at its freshest, and the confined atmosphere here isn’t helping it.”
   “Well, listen,” Donovan took another ineffectual swipe at his hair, “I’m not worried so much about our cast-iron genius and his tin ship. There’s the matter of my lost leave. And the monotony! There’s nothing here but whiskers and figures—the wrong kind of figures. Oh, why do they give us these jobs?”
   “Because,” replied Powell, gently, “we’re no loss, if they lose us. O.K., relax!—Doc Lanning’s coming this way.”
   Lanning was coming, his gray eyebrows as lavish as ever, his aged figure unbent as yet and full of life. He walked silently up the ramp with the two men and out into the open field, where, obeying no human master, silent robots were building a ship.
   Wrong tense. Had built a ship!
   For Lanning said, “The robots have stopped. Not one has moved today.”
   “It’s completed then? Definitely?” asked Powell.
   “Now how can I tell?” Lanning was peevish, and his eyebrows curled down in an eye-hiding frown. “It seems done. There are no spare pieces about, and the interior is down to a gleaming finish.”
   “You’ve been inside?”
   “Just in, then out. I’m no space-pilot. Either of you two know much about engine theory?”
   Donovan looked at Powell, who looked at Donovan.
   Donovan said, “I’ve got my license, sir, but at last reading it didn’t say anything about hyper-engines or warp-navigation. Just the usual child’s play in three dimensions.”
   Alfred Lanning looked up with sharp disapproval and snorted the length of his prominent nose.
   He said frigidly, “Well, we have our engine men.”
   Powell caught at his elbow as he walked away, “Sir, is the ship still restricted ground?”
   The old director hesitated, then rubbed the bridge of his nose, “I suppose not. For you two anyway.”
   Donovan looked after him as he left and muttered a short, expressive phrase at his back. He turned to Powell, “I’d like to give him a literary description of himself, Greg.”
   “Suppose you come along, Mike.”
   The inside of the ship was finished, as finished as a ship ever was; that could be told in a single eye-blinking glance. No martinet in the system could have put as much spit-and-polish into a surface as those robots had. The walls were of a gleaming silvery finish that retained no fingerprints.
   There were no angles; walls, floors, and ceiling faded gently into each other and in the cold, metallic glittering of the hidden lights, one was surrounded by six chilly reflections of one’s bewildered self.
   The main corridor was a narrow tunnel that led in a hard, clatter-footed stretch along a line of rooms of no interdistinguishing features.
   Powell said, “I suppose furniture is built into the wall. Or maybe we’re not supposed to sit or sleep.”
   It was in the last room, the one nearest the nose, that the monotony broke. A curving window of non-reflecting glass was the first break in the universal metal, and below it was a single large dial, with a single motionless needle hard against the zero mark.
   Donovan said, “Look at that!” and pointed to the single word on the finely-marked scale.
   It said, “Parsecs” and the tiny figure at the right end of the curving, graduated meter said “1,000,000.”
   There were two chairs; heavy, wide-flaring, uncushioned. Powell seated himself gingerly, and found it molded to the body’s curves, and comfortable.
   Powell said, “What do you think of it?”
   “For my money, The Brain has brain-fever. Let’s get out.”
   “Sure you don’t want to look it over a bit?”
   “I have looked it over. I came, I saw, I’m through!” Donovan’s red hair bristled into separate wires, “Greg, let’s get out of here. I quit my job five seconds ago, and this is a restricted area for non-personnel.”
   Powell smiled in an oily self-satisfied manner and smoothed his mustache, “O.K., Mike, turn off that adrenalin tap you’ve got draining into your bloodstream. I was worried, too, but no more.”
   “No more, huh? How come, no more? Increased your insurance?”
   “Mike, this ship can’t fly.”
   “How do you know?”
   “Well, we’ve been through the entire ship, haven’t we?”
   “Seems so.”
   “Take my word for it, we have. Did you see any pilot room except for this one port and the one gauge here in parsecs? Did you see any controls?”
   “No.”
   “And did you see any engines?”
   “Holy Joe, no!”
   “Well, then! Let’s break the news to Lanning, Mike.”
   They cursed their way through the featureless corridors and finally hit-and-missed their way into the short passage to the air lock.
   Donovan stiffened, “Did you lock this thing, Greg?”
   “No, I never touched it. Yank the lever, will you?”

   The lever never budged, though Donovan’s face twisted appallingly with exertion.
   Powell said, “I didn’t see any emergency exits. If something’s gone wrong here, they’ll have to melt us out.”
   “Yes, and we’ve got to wait until they find out that some fool has locked us in here,” added Donovan, frantically.
   “Let’s get back to the room with the port. It’s the only place from which we might attract attention.”
   But they didn’t.
   In that last room, the port was no longer blue and full of sky. It was black, and hard yellow pin-point stars spelled space.
   There was a dull, double thud, as two bodies collapsed separately into two chairs.
   Alfred Lanning met Dr. Calvin just outside his office. He lit a nervous cigar and motioned her in.
   He said, “Well, Susan, we’ve come pretty far, and Robertson’s getting jumpy. What are you doing with The Brain?”
   Susan Calvin spread her hands, “It’s no use getting impatient. The Brain is worth more than anything we forfeit on this deal.”
   “But you’ve been questioning it for two months.”
   The psychologist’s voice was flat, but somehow dangerous, “You would rather run this yourself?”
   “Now you know what I meant.”
   “Oh, I suppose I do,” Dr. Calvin rubbed her hands nervously. “It isn’t easy. I’ve been pampering it and probing it gently, and I haven’t gotten anywhere yet. Its’ reactions aren’t normal. Its answers—they’re queer, somehow. But nothing I can put my finger on yet. And you see, until we know what’s wrong, we must just tiptoe our way through. I can never tell what simple question or remark will just … push him over … and then—Well, and then we’ll have on our hands a completely useless Brain. Do you want to face that?”
   “Well, it can’t break the First Law.”
   “I would have thought so, but—”
   “You’re not even sure of that?” Lanning was profoundly shocked.
   “Oh, I can’t be sure of anything, Alfred—”
   The alarm system raised its fearful clangor with a horrifying suddenness. Lanning clicked on communications with an almost paralytic spasm. The breathless words froze him.
   He said, “Susan … you heard that … the ship’s gone. I sent those two field men inside half an hour ago. You’ll have to see The Brain again.”
   Susan Calvin said with enforced calm, “Brain, what happened to the ship?”
   The Brain said happily, “The ship I built, Miss Susan?”
   “That’s right. What has happened to it?”
   “Why, nothing at all. The two men that were supposed to test it were inside, and we were all set. So I sent it off.”
   “Oh—Well, that’s nice.” The psychologist felt some difficulty in breathing. “Do you think they’ll be all right?”
   “Right as anything, Miss Susan. I’ve taken care of it all. It’s a bee-yootiful ship.”
   “Yes, Brain, it is beautiful, but you think they have enough food, don’t you? They’ll be comfortable?”
   “Plenty of food.”
   “This business might be a shock to them, Brain. Unexpected, you know.”
   The Brain tossed it off, “They’ll be all right. It ought to be interesting for them.”
   “Interesting? How?”
   “Just interesting,” said The Brain, slyly.
   “Susan,” whispered Lanning in a fuming whisper, “ask him if death comes into it. Ask him what the dangers are.”
   Susan Calvin’s expression contorted with fury, “Keep quiet!” In a shaken voice, she said to The Brain, “We can communicate with the ship, can’t we Brain?”
   “Oh, they can hear you if you call by radio. I’ve taken care of that.”
   “Thanks. That’s all for now.”
   Once outside, Lanning lashed out ragingly, “Great Galaxy, Susan, if this gets out, it will ruin all of us. We’ve got to get those men back. Why didn’t you ask it if there was danger of death—straight out?”
   “Because,” said Calvin, with a weary frustration, “that’s just what I can’t mention. If it’s got a case of dilemma, it’s about death. Anything that would bring it up badly might knock it completely out. Will we be better off then? Now, look, it said we could communicate with them. Let’s do so, get their location, and bring them back. They probably can’t use the controls themselves; The Brain is probably handling them remotely. Come!”
   It was quite a while before Powell shook himself together.
   “Mike,” he said, out of cold lips, “did you feel an acceleration?”
   Donovan’s eyes were blank, “Huh? No … no.”
   And then the redhead’s fists clenched and he was out of his seat with sudden frenzied energy and up against the cold, wide-curving glass. There was nothing to see—but stars.
   He turned, “Greg, they must have started the machine while we were inside. Greg, it’s a put-up job; they fixed it up with the robot to jerry us into being the try-out boys, in case we were thinking of backing out.”
   Powell said, “What are you talking about? What’s the good of sending us out if we don’t know how to run the machine? How are we supposed to bring it back? No, this ship left by itself, and without any apparent acceleration.” He rose, and walked the floor slowly. The metal walls dinned back the clangor of his steps.
   He said tonelessly, “Mike, this is the most confusing situation we’ve ever been up against.”
   “That,” said Donovan, bitterly, “is news to me. I was just beginning to have a very swell time, when you told me.”
   Powell ignored that. “No acceleration—which means the ship works on a principle different from any known.”
   “Different from any we know, anyway.”
   “Different from any known. There are no engines within reach of manual control. Maybe they’re built into the walls. Maybe that’s why they’re thick as they are.”
   “What are you mumbling about?” demanded Donovan.
   “Why not listen? I’m saying that whatever powers this ship is enclosed, and evidently not meant to be handled. The ship is running by remote control.”
   “The Brain’s control?”
   “Why not?”
   “Then you think we’ll stay out here till The Brain brings us back.”
   “It could be. If so, let’s wait quietly. The Brain is a robot. It’s got to follow the First Law. It can’t hurt a human being.”
   Donovan sat down slowly, “You figure that?” Carefully, he flattened his hair, “Listen, this junk about the space-warp knocked out Consolidated’s robot, and the longhairs said it was because interstellar travel killed humans. Which robot are you going to trust? Ours had the same data, I understand.”
   Powell was yanking madly at his mustache, “Don’t pretend you don’t know your robotics, Mike. Before it’s physically possible in any way for a robot to even make a start to breaking the First Law, so many things have to break down that it would be a ruined mess of scrap ten times over. There’s some simple explanation to this.”
   “Oh sure, sure. Just have the butler call me in the morning. It’s all just too, too simple for me to bother about before my beauty nap.”
   “Well, Jupiter, Mike, what are you complaining about so far? The Brain is taking care of us. This place is warm. It’s got light. It’s got air. There wasn’t even enough of an acceleration jar to muss your hair if it were smooth enough to be mussable in the first place.”
   “Yeah? Greg, you must’ve taken lessons. No one could put Pollyanna that far out of the running without. What do we eat? What do we drink? Where are we? How do we get back? And in case of accident, to what exit and in what spacesuit do we run, not walk? I haven’t even seen a bathroom in the place, or those little conveniences that go along with bathrooms. Sure, we’re being taken care of—but good?”
   The voice that interrupted Donovan’s tirade was not Powell’s. It was nobody’s. It was there, hanging in open air—stentorian and petrifying in its effects.
   “GREGORY POWELL! MICHAEL DONOVAN! GREGORY POWELL! MICHAEL DONOVAN! PLEASE REPORT YOUR PRESENT POSITIONS. IF YOUR SHIP ANSWERS CONTROLS, PLEASE RETURN TO BASE. GREGORY POWELL! MICHAEL DONOVAN!—”
   The message was repetitious, mechanical, broken by regular, untiring intervals.
   Donovan said, “Where’s it coming from?”
   “I don’t know.” Powell’s voice was an intense whisper, “Where do the lights come from? Where does anything come from?”
   “Well, how are we going to answer?” They had to speak in the intervals between the loudly echoing, repeating message.
   The walls were bare—as bare and as unbroken as smooth, curving metal can be. Powell said, “Shout an answer.”
   They did. They shouted, in turns, and together, “Position unknown! Ship out of control! Condition desperate!”
   Their voices rose and cracked. The short businesslike sentences became interlarded and adulterated with screaming and emphatic profanity, but the cold, calling voice repeated and repeated and repeated unwearyingly.
   “They don’t hear us,” gasped Donovan. “There’s no sending mechanism. Just a receiver.” His eyes focused blindly at a random spot on the wall.
   Slowly the din of the outside voice softened and receded. They called again when it was a whisper, and they called again, hoarsely, when there was silence.
   Something like fifteen minutes later, Powell said lifelessly, “Let’s go through the ship again. There must be something to eat somewheres.” He did not sound hopeful. It was almost an admission of defeat.
   They divided in the corridor to the right and left. They could follow one another by the hard footsteps resounding, and they met occasionally in the corridor, where they would glare at each other and pass on.
   Powell’s search ended suddenly and as it did, he heard Donovan’s glad voice rise boomingly.
   “Hey, Greg,” it howled, “The ship has got plumbing. How did we miss it?”
   It was some five minutes later that he found Powell by hit-and-miss. He was saying, “Still no shower baths, though,” but it got choked off in the middle.
   “Food,” he gasped.
   The wall had dropped away, leaving a curved gap with two shelves. The upper shelf was loaded with unlabeled cans of a bewildering variety of sizes and shapes. The enameled cans on the lower shelf were uniform and Donovan felt a cold draft about his ankles. The lower half was refrigerated.
   “How … how—”
   “It wasn’t there, before,” said Powell, curtly. “That wall section dropped out of sight as I came in the door.”
   He was eating. The can was the preheating type with enclosed spoon and the warm odor of baked beans filled the room. “Grab a can, Mike!”
   Donovan hesitated, “What’s the menu?”
   “How do I know! Are you finicky?”
   “No, but all I eat on ships are beans. Something else would be first choice.” His hand hovered and selected a shining elliptical can whose flatness seemed reminiscent of salmon or similar delicacy. It opened at the proper pressure.
   “Beans!” howled Donovan, and reached for another. Powell hauled at the slack of his pants. “Better eat that, sonny boy. Supplies are limited and we may be here a long, long time.”
   Donovan drew back sulkily, “Is that all we have? Beans?”
   “Could be.”
   “What’s on the lower shelf?”
   “Milk.”
   “Just milk?” Donovan cried in outrage.

   “Looks it.”
   The meal of beans and milk was carried through in silence, and as they left, the strip of hidden wall rose up and formed an unbroken surface once more.
   Powell sighed, “Everything automatic. Everything just so. Never felt so helpless in my life. Where’s your plumbing?”
   “Right there. And that wasn’t among those present when we first looked, either.”
   Fifteen minutes later they were back in the glassed-in room, staring at each other from opposing seats.
   Powell looked gloomily at the one gauge in the room. It still said “parsecs,” the figures still ended in “1,000,000” and the indicating needle was still pressed hard against the zero mark.
   In the innermost offices of the U. S. Robot & Mechanical Men Corp. Alfred Lanning was saying wearily, “They won’t answer. We’ve tried every wavelength, public, private, coded, straight, even this subether stuff they have now. And The Brain still won’t say anything?” He shot this at Dr. Calvin.
   “It won’t amplify on the matter, Alfred,” she said, emphatically. “It says they can hear us … and when I try to press it, it becomes … well, it becomes sullen. And it’s not supposed to—whoever heard of a sullen robot?”
   “Suppose you tell us what you have, Susan,” said Bogert.
   “Here it is! It admits it controls the ship itself entirely. It is definitely optimistic about their safety, but without details. I don’t dare press it. However, the center of disturbance seems to be about the interstellar jump itself. The Brain definitely laughed when I brought up the subject. There are other indications, but that is the closest it’s come to an open abnormality.”
   She looked at the others, “I refer to hysteria. I dropped the subject immediately, and I hope I did no harm, but it gave me a lead. I can handle hysteria. Give me twelve hours! If I can bring it back to normal, it will bring back the ship.”
   Bogert seemed suddenly stricken. “The interstellar jump!”
   “What’s the matter?” The cry was double from Calvin and Lanning.
   “The figures for the engine The Brain gave us. Say … I just thought of something.”
   He left hurriedly.
   Lanning gazed after him. He said brusquely to Calvin, “You take care of your end, Susan.”
   Two hours later, Bogert was talking eagerly, “I tell you, Lanning, that’s it. The interstellar jump is not instantaneous not as long as the speed of light is finite. Life can’t exist … matter and energy as such can’t exist in the space warp. I don’t know what it would be like—but that’s it. That’s what killed Consolidated’s robot.”
   Donovan felt as haggard as he looked. “Only five days?”
   “Only five days. I’m sure of it.”
   Donovan looked about him wretchedly. The stars through the glass were familiar but infinitely indifferent. The walls were cold to the touch; the lights, which had recently flared up again, were unfeelingly bright; the needle on the gauge pointed stubbornly to zero; and Donovan could not get rid of the taste of beans.
   He said, morosely, “I need a bath.”
   Powell looked up briefly, and said, “So do I. You needn’t feel self-conscious. But unless you want to bathe in milk and do without drinking”
   “We’ll do without drinking eventually, anyway. Greg, where does this interstellar travel come in?’
   “You tell me. Maybe we just keep on going. We’d get there, eventually. At least the dust of our skeletons would—but isn’t our death the whole point of The Brain’s original breakdown?”
   Donovan spoke with his back to the other, “Greg, I’ve been thinking. It’s pretty bad. There’s not much to do—except walk around or talk to yourself. You know those stories about guys marooned in space. They go nuts long before they starve. I don’t know, Greg, but ever since the lights went on, I feel funny.”
   There was a silence, then Powell’s voice came thin and small, “So do I. What’s it like?”
   The redheaded figure turned, “Feel funny inside. There’s a pounding in me with everything tense. It’s hard to breathe. I can’t stand still.”
   “Um-m-m. Do you feel vibration?”
   “How do you mean?”
   “Sit down for a minute and listen. You don’t hear it, but you feel it—as if something’s throbbing somewheres and it’s throbbing the whole ship, and you, too, along with it. Listen—”
   “Yeah … yeah. What do you think it is, Greg? You don’t suppose it’s us?”
   “It might be.” Powell stroked his mustache slowly. “But it might be the ship’s engines. It might be getting ready.”
   “For what?”
   “For the interstellar jump. It may be coming and the devil knows what it’s like.”
   Donovan pondered. Then he said, savagely, “If it does, let it. But I wish we could fight. It’s humiliating to have to wait for it.”
   An hour later, perhaps, Powell looked at his hand on the metal chair-arm and said with frozen calm, “Feel the wall, Mike.”
   Donovan did, and said, “You can feel it shake, Greg.”
   Even the stars seemed blurred. From somewhere came the vague impression of a huge machine gathering power with the walls, storing up energy for a mighty leap, throbbing its way up the scales of strength.
   It came with a suddenness and a stab of pain. Powell stiffened, and half-jerked from his chair. His sight caught Donovan and blanked out while Donovan’s thin shout whimpered and died in his ears. Something writhed within him and struggled against a growing blanket of ice, that thickened.
   Something broke loose and whirled in a blaze of flickering light and pain. It fell—and whirled and fell headlong into silence!
   It was death!
   It was a world of no motion and no sensation. A world of dim, unsensing consciousness; a consciousness of darkness and of silence and of formless struggle.
   Most of all a consciousness of eternity.
   He was a tiny white thread of ego—cold and afraid.
   Then the words came, unctuous and sonorous, thundering over him in a foam of sound:
   “Does your coffin fit differently lately? Why not try Morbid M. Cadaver’s extensible caskets? They are scientifically designed to fit the natural curves of the body, and are enriched with Vitamin B1. Use Cadaver’s caskets for comfort. Remember—you’re—going—to—be—dead—a—long—long—time!”
   It wasn’t quite sound, but whatever it was, it died away in an oily rumbling whisper.
   The white thread that might have been Powell heaved uselessly at the insubstantial eons of time that existed all about him—and collapsed upon itself as the piercing shriek of a hundred million ghosts of a hundred million soprano voices rose to a crescendo of melody:
   “I’ll be glad when you’re dead, you rascal, you.
   “I’ll be glad when you’re dead, you rascal, you.
   “I’ll be glad—”
   It rose up a spiral stairway of violent sound into the keening supersonics that passed hearing, and then beyond-
   The white thread quivered with a pulsating pang. It strained quietly-
   The voices were ordinary—and many. It was a crowd speaking; a swirling mob that swept through and past and over him with a rapid, headlong motion, that left drifting tatters of words behind them.
   “What did they getcha for, boy? Y’look banged up—”
   “—A hot fire, I guess, but I got a case—”
   “—I’ve made Paradise, but old St. Pete—”
   “Naaah, I got a pull with the boy. Had dealings with him—”
   “Hey, Sam, come this way—”
   “Ja get a mouthpiece? Beelzebub says—”
   “—Going on, my good imp? My appointment is with Sa—”
   And above it all the original stentorian roar, that plunged across all:
   “HURRY! HURRY! HURRY!!! Stir your bones, and don’t keep us waiting—there are many more in line. Have your certificates ready, and make sure Peter’s release is stamped across it. See if you are at the proper entrance gate. There will be plenty of fire for all. Hey, you—YOU DOWN THERE. TAKE YOUR PLACE IN LINE OR—”
   The white thread that was Powell groveled backward before the advancing shout, and felt the sharp stab of the pointing finger. It all exploded into a rainbow of sound that dripped its fragments onto an aching brain.
   Powell was in the chair, again. He felt himself shaking.
   Donovan’s eyes were opening into two large popping bowls of glazed blue.
   “Greg,” he whispered in what was almost a sob. “Were you dead?”
   “I … felt dead.” He did not recognize his own croak.
   Donovan was obviously making a bad failure of his attempt to stand up, “Are we alive now? Or is there more?”
   “I … feel alive.” It was the same hoarseness. Powell said cautiously, “Did you … hear anything, when … when you were dead?”
   Donovan paused, and then very slowly nodded his head, “Did you?”
   “Yes. Did you hear about coffins … and females singing … and the lines forming to get into Hell? Did you?”
   Donovan shook his head, “Just one voice.”
   “Loud?”
   “No. Soft, but rough like a file over the fingertips. It was a sermon, you know. About hell-fire. He described the tortures of … well, you know. I once heard a sermon like that—almost.”
   He was perspiring.
   They were conscious of sunlight through the port. It was weak, but it was blue-white—and the gleaming pea that was the distant source of light was not Old Sol.
   And Powell pointed a trembling finger at the single gauge. The needle stood stiff and proud at the hairline whose figure read 300,000 parsecs.
   Powell said, “Mike if it’s true, we must be out of the Galaxy altogether.”
   Donovan said, “Blazed Greg! We’d be the first men out of the Solar System.”
   “Yes! That’s just it. We’ve escaped the sun. We’ve escaped the Galaxy. Mike, this ship is the answer. It means freedom for all humanity—freedom to spread through to every star that exists—millions and billions and trillions of them.”
   And then he came down with a hard thud, “But how do we get back, Mike?”
   Donovan smiled shakily, “Oh, that’s all right. The ship brought us here. The ship will take us back. Me for more beans.”
   “But Mike … hold on, Mike. If it takes us back the way it brought us here—”
   Donovan stopped halfway up and sat back heavily into the chair.
   Powell went on, “We’ll have to … die again, Mike”
   “Well,” sighed Donovan, “if we have to, we have to. At least it isn’t permanent, not very permanent.”
   Susan Calvin was speaking slowly now. For six hours she had been slowly prodding The Brain—for six fruitless hours. She was weary of repetitions, weary of circumlocutions, weary of everything.
   “Now, Brain, there’s just one more thing. You must make a special effort to answer simply. Have you been entirely clear about the interstellar jump? I mean does it take them very far?”

   “As far as they want to go, Miss Susan. Golly, it isn’t any trick through the warp.”
   “And on the other side, what will they see?”
   “Stars and stuff. What do you suppose?”
   The next question slipped out, “They’ll be alive, then?”
   “Sure!”
   “And the interstellar jump won’t hurt them?”
   She froze as The Brain maintained silence. That was it! She had touched the sore spot.
   “Brain,” she supplicated faintly, “Brain, do you hear me?”
   The answer was weak, quivering. The Brain said, “Do I have to answer? About the jump, I mean?”
   “Not if you don’t want to. But it would be interesting—I mean if you wanted to.” Susan Calvin tried to be bright about it.
   “Aw-w-w. You spoil everything.”
   And the psychologist jumped up suddenly, with a look of flaming insight on her face.
   “Oh, my,” she gasped. “Oh, my.”
   And she felt the tension of hours and days released in a burst. It was later that she told Lanning, “I tell you it’s all right. No, you must leave me alone, now. The ship will be back safely, with the men, and I want to rest. I will rest. Now go away.”
   The ship returned to Earth as silently, as unjarringly as it had left. It dropped precisely into place and the main lock gaped open. The two men who walked out felt their way carefully and scratched their rough and scrubbily-stubbled chins.
   And then, slowly and purposefully, the one with red hair knelt down and planted upon the concrete of the runway a firm, loud kiss.
   They waved aside the crowd that was gathering and made gestures of denial at the eager couple that had piled out of the down-swooping ambulance with a stretcher between them.
   Gregory Powell said, “Where’s the nearest shower?”
   They were led away.
   They were gathered, all of them, about a table. It was a full staff meeting of the brains of U. S. Robot & Mechanical Men Corp.
   Slowly and climactically, Powell and Donovan finished a graphic and resounding story.
   Susan Calvin broke the silence that followed. In the few days that had elapsed she had recovered her icy, somewhat acid, calm—but still a trace of embarrassment broke through.
   “Strictly speaking,” she said, “this was my fault—all of it. When we first presented this problem to The Brain, as I hope some of you remember, I went to great lengths to impress upon it the importance of rejecting any item of information capable of creating a dilemma. In doing so I said something like ‘Don’t get excited about the death of humans. We don’t mind it at all. Just give the sheet back and forget it.’“
   “Hm-m-m,” said Lanning. “What follows?”
   “The obvious. When that item entered its calculations which yielded the equation controlling the length of minimum interval for the interstellar jump—it meant death for humans. That’s where Consolidated’s machine broke down completely. But I had depressed the importance of death to The Brain—not entirely, for the First Law can never be broken—but just sufficiently so that The Brain could take a second look at the equation. Sufficiently to give it time to realize that after the interval was passed through, the men would return to life—just as the matter and energy of the ship itself would return to being. This so-called ‘death,’ in other words, was a strictly temporary phenomenon. You see?”
   She looked about her. They were all listening.
   She went on, “So he accepted the item, but not without a certain jar. Even with death temporary and its importance depressed, it was enough to unbalance him very gently.”
   She brought it out calmly, “He developed a sense of humor—it’s an escape, you see, a method of partial escape from reality. He became a practical joker.”
   Powell and Donovan were on their feet.
   “What?” cried Powell?
   Donovan was considerably more colorful about it.
   “It’s so,” said Calvin. “He took care of you, and kept you safe, but you couldn’t handle any controls, because they weren’t for you—just for the humorous Brain. We could reach you by radio, but you couldn’t answer. You had plenty of food, but all of it beans and milk. Then you died, so to speak, and were reborn, but the period of your death was made … well … interesting. I wish I knew how he did it. It was The Brain’s prize joke, but he meant no harm.”
   “No harm!” gasped Donovan. “Oh, if that cute little tyke only had a neck.”
   Lanning raised a quieting hand, “All right, it’s been a mess, but it’s all over. What now?”
   “Well,” said Bogert, quietly, “obviously it’s up to us to improve the space-warp engine. There must be some way of getting around that interval of jump. If there is, we’re the only organization left with a grand-scale super-robot, so we’re bound to find it if anyone can. And then—U. S. Robots has interstellar travel, and humanity has the opportunity for galactic empire.”
   “What about Consolidated?” said Lanning?
   “Hey,” interrupted Donovan suddenly, “I want to make a suggestion there. They landed U. S. Robots into quite a mess. It wasn’t as bad a mess as they expected and it turned out well, but their intentions weren’t pious. And Greg and I bore the most of it.
   “Well, they wanted an answer, and they’ve got one. Send them that ship, guaranteed, and U. S. Robots can collect their two hundred thou plus construction costs. And if they test it—then suppose we let The Brain have just a little more fun before it’s brought back to normal.”
   Lanning said gravely, “It sounds just and proper to me.”
   To which Bogert added absently, “Strictly according to contract, too.”