Powell seemed determined to push up his mustache by the roots. He said, “There is nothing wrong with the currents of his positronic brain.”
   “I’d hate to be that certain.”
   “Oh, Jupiter, Mike! The brain is the surest part of a robot. It’s quintuple-checked back on Earth. If they pass the field test perfectly, the way Dave did, there just isn’t a chance of brain misfunction. That test covered every key path in the brain.”
   “So where are we?”
   “Don’t rush me. Let me work this out. There’s still the possibility of a mechanical breakdown in the body. That leaves about fifteen hundred condensers, twenty thousand individual electric circuits, five hundred vacuum cells, a thousand relays, and upty-ump thousand other individual pieces of complexity that can be wrong. And these mysterious positron is fields no one knows anything about.”
   “Listen, Greg,” Donovan grew desperately urgent. “I’ve got an idea. That robot may be lying. He never—”
   “Robots can’t knowingly lie, you fool. Now if we had the McCormack-Wesley tester, we could check each individual item in his body within twenty-four to forty-eight hours, but the only two M-W testers existing are on Earth, and they weigh ten tons, are on concrete foundations and can’t be moved. Isn’t that peachy?”
   Donovan pounded the desk, “But, Greg, he only goes wrong when we’re not around. There’s something—sinister—about—that.” He punctuated the sentence with slams of fist against desk.
   “You,” said Powell, slowly, “make me sick. You’ve been reading adventure novels.”
   “What I want to know,” shouted Donovan, “is what we’re going to do about it.”
   “I’ll tell you. I’m going to install a visiplate right over my desk. Right on the wall over there, see!” He jabbed a vicious finger at the spot. “Then I’m going to focus it at whatever part of the mine is being worked, and I’m going to watch. That’s all.”
   “That’s all? Greg—”
   Powell rose from his chair and leaned his balled fists on the desk, “Mike, I’m having a hard time.” His voice was weary. “For a week, you’ve been plaguing me about Dave. You say he’s gone wrong. Do you know how he’s gone wrong? No! Do you know what shape this wrongness takes? No! Do you know what brings it on? No! Do you know what snaps him out? No! Do you know anything about it? No! Do I know anything about it? No! So what do you want me to do?”
   Donovan’s arm swept outward in a vague, grandiose gesture, “You got me!”
   “So I tell you again. Before we do anything toward a cure, we’ve got to find out what the disease is in the first place. The first step in cooking rabbit stew is catching the rabbit. Well, we’ve got to catch that rabbit! Now get out of here.”
   Donovan stared at the preliminary outline of his field report with weary eyes. For one thing, he was tired and for another, what was there to report while things were unsettled? He felt resentful.
   He said, “Greg, we’re almost a thousand tons behind schedule.”
   “You,” replied Powell, never looking up, “are telling me something I don’t know.”
   “What I want to know,” said Donovan, in sudden savagery, “is why we’re always tangled up with new-type robots. I’ve finally decided that the robots that were good enough for my great-uncle on my mother’s side are good enough for me. I’m for what’s tried and true. The test of time is what counts—good, solid, old-fashioned robots that never go wrong.”
   Powell threw a book with perfect aim, and Donovan went tumbling off his seat.
   “Your job,” said Powell, evenly, “for the last five years has been to test new robots under actual working conditions for United States Robots. Because you and I have been so injudicious as to display proficiency at the task, we’ve been rewarded with the dirtiest jobs. That,” he jabbed holes in the air with his finger in Donovan’s direction, “is your work. You’ve been griping about it, from personal memory, since about five minutes after United States Robots signed you up. Why don’t you resign?”
   “Well, I’ll tell you.” Donovan rolled onto his stomach, and took a firm grip on his wild, red hair to hold his head up. “There’s a certain principle involved. After all, as a troubleshooter, I’ve played a part in the development of new robots. There’s the principle of aiding scientific advance. But don’t get me wrong. It’s not the principle that keeps me going; it’s the money they pay us. Greg!’
   Powell jumped at Donovan’s wild shout, and his eyes followed the redhead’s to the visiplate, when they goggled in fixed horror. He whispered, “Holy—howling—Jupiter!”
   Donovan scrambled breathlessly to his feet, “Look at them, Greg. They’ve gone nuts.”
   Powell said, “Get a pair of suits. We’re going out there.”
   He watched the posturings of the robots on the visiplate. They were bronzy gleams of smooth motion against the shadowy crags of the airless asteroid. There was a marching formation now, and in their own dim body light, the roughhewn walls of the mine tunnel swam past noiselessly, checkered with misty erratic blobs of shadow. They marched in unison, seven of them, with Dave at the head. They wheeled and turned in macabre simultaneity; and melted through changes of formation with the weird ease of chorus dancers in Lunar Bowl.
   Donovan was back with the suits, “They’ve gone jingo on us, Greg. That’s a military march.”
   “For all you know,” was the cold response, “it may be a series of callisthenic exercises. Or Dave may be under the hallucination of being a dancing master. Just you think first, and don’t bother to speak afterward, either.”
   Donovan scowled and slipped a detonator into the empty side holster with an ostentatious shove. He said, “Anyway, there you are. So we work with new-model robots. It’s our job, granted. But answer me one question. Why … why does something invariably go wrong with them?”
   “Because,” said Powell, somberly, “we are accursed. Let’s go!”
   Far ahead through the thick velvety blackness of the corridors that reached past the illuminated circles of their flashlights, robot light twinkled.
   “There they are,” breathed Donovan.
   Powell whispered tensely, “I’ve been trying to get him by radio but he doesn’t answer. The radio circuit is probably out.”
   “Then I’m glad the designers haven’t worked out robots who can work in total darkness yet. I’d hate to have to find seven mad robots in a black pit without radio communication, if they weren’t lit up like blasted radioactive Christmas trees.”
   “Crawl up on the ledge above, Mike. They’re coming this way, and I want to watch them at close range. Can you make it?”
   Donovan made the jump with a grunt. Gravity was considerably below Earth-normal, but with a heavy suit, the advantage was not too great, and the ledge meant a near ten-foot jump. Powell followed.
   The column of robots was trailing Dave single-file. In mechanical rhythm, they converted to double and returned to single in different order. It was repeated over and over again and Dave never turned his head.
   Dave was within twenty feet when the play-acting ceased. The subsidiary robots broke formation, waited a moment, then clattered off into the distance—very rapidly. Dave looked after them, then slowly sat down. He rested his head in one hand in a very human gesture.
   His voice sounded in Powell’s earphones, “Are you here, boss?”
   Powell beckoned to Donovan and hopped off the ledge.
   “O.K., Dave, what’s been going on?”
   The robot shook his head, “I don’t know. One moment I was handling a tough outcropping in Tunnel 17, and the next I was aware of humans close by, and I found myself half a mile down main-stem.”
   “Where are the subsidiaries now?” asked Donovan.
   “Back at work, of course. How much time has been lost?”
   “Not much. Forget it.” Then to Donovan, Powell added, “Stay with him the rest of the shift. Then, come back. I’ve got a couple of ideas.”
   It was three hours before Donovan returned. He looked tired. Powell said, “How did it go?”
   Donovan shrugged wearily, “Nothing ever goes wrong when you watch them. Throw me a butt, will you?”
   The redhead lit it with exaggerated care and blew a careful smoke ring. He said, “I’ve been working it out, Greg. You know, Dave has a queer background for a robot. There are six others under him in an extreme regimentation. He’s got life and death power over those subsidiary robots and it must react on his mentality. Suppose he finds it necessary to emphasize this power as a concession to his ego.”
   “Get to the point.”
   “It’s right here. Suppose we have militarism. Suppose he’s fashioning himself an army. Suppose—he’s training them in military maneuvers. Suppose—”
   “Suppose you go soak your head. Your nightmares must be in technicolor. You’re postulating a major aberration of the positronic brain. If your analysis were correct, Dave would have to break down the First Law of Robotics: that a robot may not injure a human being or, through inaction, allow a human being to be injured. The type of militaristic attitude and domineering ego you propose must have as the end-point of its logical implications, domination of humans.”
   “All right. How do you know that isn’t the fact of the matter?”
   “Because any robot with a brain like that would, one, never have left the factory, and two, be spotted immediately if it ever was. I tested Dave, you know.”
   Powell shoved his chair back and put his feet on the desk. “No. We’re still in the position where we can’t make our stew because we haven’t the slightest notion as to what’s wrong. For instance, if we could find out what that dance macabre we witnessed was all about, we would be on the way out.”
   He paused, “Now listen, Mike, how does this sound to you? Dave goes wrong only when neither of us is present. And when he is wrong, the arrival of either of us snaps him out of it.”

   “I once told you that was sinister.”
   “Don’t interrupt. How is a robot different when humans are not present? The answer is obvious. There is a larger requirement of personal initiative. In that case, look for the body parts that are affected by the new requirements.”
   “Golly.” Donovan sat up straight, then subsided. “No, no. Not enough. It’s too broad. It doesn’t cut the possibilities much.”
   “Can’t help that. In any case, there’s no danger of not making quota. We’ll take shifts watching those robots through the visor. Any time anything goes wrong, we get to the scene of action immediately. That will put them right.”
   “But the robots will fail spec anyway, Greg. United States Robots can’t market DV models with a report like that.”
   “Obviously. We’ve got to locate the error in make-up and correct it—and we’ve got ten days to do it in.” Powell scratched his head. “The trouble is … well, you had better look at the blueprints yourself.”
   The blueprints covered the floor like a carpet and Donovan crawled over the face of them following Powell’s erratic pencil.
   Powell said, “Here’s where you come in, Mike. You’re the body specialist, and I want you to check me. I’ve been trying to cut out all circuits not involved in the personal initiative hookup. Right here, for instance, is the trunk artery involving mechanical operations. I cut out all routine side routes as emergency divisions—” He looked up, “What do you think?”
   Donovan had a very bad taste in his mouth, “The job’s not that simple, Greg. Personal initiative isn’t an electric circuit you can separate from the rest and study. When a robot is on his own, the intensity of the body activity increases immediately on almost all fronts. There isn’t a circuit entirely unaffected. What must be done is to locate the particular condition—a very specific condition—that throws him off, and then start eliminating circuits.”
   Powell got up and dusted himself, “Hmph. All right. Take away the blueprints and burn them.”
   Donovan said, “You see when activity intensifies, anything can happen, given one single faulty part. Insulation breaks down, a condenser spills over, a connection sparks, a coil overheats. And if you work blind, with the whole robot to choose from, you’ll never find the bad spot. If you take Dave apart and test every point of his body mechanism one by one, putting him together each time, and trying him out”
   “All right. All right. I can see through a porthole, too.”
   They faced each other hopelessly, and then Powell said cautiously, “Suppose we interview one of the subsidiaries.”
   Neither Powell nor Donovan had ever had previous occasion to talk to a “finger.” It could talk; it wasn’t quite the perfect analogy to a human finger. In fact, it had a fairly developed brain, but that brain was tuned primarily to the reception of orders via positronic field, and its reaction to independent stimuli was rather fumbling.
   Nor was Powell certain as to its name. Its serial number was DV-5-2, but that was not very useful.
   He compromised. “Look, pal,” he said, “I’m going to ask you to do some hard thinking and then you can go back to your boss.”
   The “finger” nodded its head stiffly, but did not exert its limited brainpower on speech.
   “Now on four occasions recently,” Powell said, “your boss deviated from brain-scheme. Do you remember those occasions?”
   “Yes, sir.”
   Donovan growled angrily, “He remembers. I tell you there is something very sinister—”
   “Oh, go bash your skull. Of course, the ‘finger’ remembers. There is nothing wrong with him.” Powell turned back to the robot, “What were you doing each time … I mean the whole group”
   The “finger” had a curious air of reciting by rote, as if he answered questions by the mechanical pressure of his brainpan, but without any enthusiasm whatever.
   He said, “The first time we were at work on a difficult outcropping in Tunnel 17, Level B. The second time we were buttressing the roof against a possible cave-in. The third time we were preparing accurate blasts in order to tunnel farther without breaking into a subterranean fissure. The fourth time was just after a minor cave-in”
   “What happened at these times?”
   “It is difficult to describe. An order would be issued, but before we could receive and interpret it, a new order came to march in queer formation.”
   Powell snapped out, “Why?”
   “I don’t know.”
   Donovan broke in tensely, “What was the first order … the one that was superseded by the marching directions?”
   “I don’t know. I sensed that an order was sent, but there was never time to receive it.”
   “Could you tell us anything about it? Was it the same order each time?”
   The “finger” shook his head unhappily, “I don’t know.”
   Powell leaned back, “All right, get back to your boss.”
   The “finger” left, with visible relief.
   Donovan said, “Well, we accomplished a lot that time. That was real sharp dialogue all the way through. Listen, Dave and that imbecile ‘finger’ are both holding out on us. There is too much they don’t know and don’t remember. We’ve got to stop trusting them, Greg.”
   Powell brushed his mustache the wrong way, “So help me, Mike, another fool remark out of you, and I’ll take away your rattle and teething ring.”
   “All right. You’re the genius of the team. I’m just a poor sucker. Where do we stand?”
   “Right behind the eight ball. I tried to work it backward through the ‘finger,’ and couldn’t. So we’ve got to work it forward.”
   “A great man,” marveled Donovan. “How simple that makes it. Now translate that into English, Master.”
   “Translating it into baby talk would suit you better. I mean that we’ve got to find out what order it is that Dave gives just before everything goes black. It would be the key to the business.”
   “And how do you expect to do that? We can’t get close to him because nothing will go wrong as long as we are there. We can’t catch the orders by radio because they are transmitted via this positronic field. That eliminates the close-range and the long-range method, leaving us a neat, cozy zero.”
   “By direct observation, yes. There’s still deduction.”
   “Huh?”
   “We’re going on shifts, Mike.” Powell smiled grimly. “And we are not taking our eyes off the visiplate. We’re going to watch every action of those steel headaches. When they go off into their act, we’re going to see what happened immediately before and we’re going to deduce the order.”
   Donovan opened his mouth and left it that way for a full minute. Then he said in strangled tones, “I resign. I quit.”
   “You have ten days to think up something better,” said Powell wearily.
   Which, for eight days, Donovan tried mightily to do. For eight days, on alternate four-hour shifts, he watched with aching and bleary eyes those glinty metallic forms move against the vague background. And for eight days in the four-hour in-betweens, he cursed United States Robots, the DV models, and the day he was born.
   And then on the eighth day, when Powell entered with an aching head and sleepy eyes for his shift, Donovan stood up and with very careful and deliberate aim launched a heavy bookend for the exact center of the visiplate. There was a very appropriate splintering noise.
   Powell gasped, “What did you do that for?”
   “Because,” said Donovan, almost calmly, “I’m not watching it any more. We’ve got two days left and we haven’t found out a thing. DV-5 is a lousy loss. He’s stopped five times since I’ve been watching and three times on your shift, and I can’t make out what orders he gave, and you couldn’t make it out. And I don’t believe you could ever make it out because I know I couldn’t ever.”
   “Jumping Space, how can you watch six robots at the same time? One makes with the hands, and one with the feet and one like a windmill and another is jumping up and down like a maniac. And the other two … devil knows what they are doing. And then they all stop. So! So!”
   “Greg, we’re not doing it right. We got to get up close. We’ve got to watch what they’re doing from where we can see the details.”
   Powell broke a bitter silence. “Yeah, and wait for something to go wrong with only two days to go.”
   “Is it any better watching from here?”
   “It’s more comfortable.”
   “Ah—But there’s something you can do there that you can’t do here.”
   “What’s that?”
   “You can make them stop—at whatever time you choose and while you’re prepared and watching to see what goes wrong.”
   Powell startled into alertness, “Howzzat?”
   “Well, figure it out, yourself. You’re the brains you say. Ask yourself some questions. When does DV-5 go out of whack? When did that ‘finger’ say he did? When a cave-in threatened, or actually occurred, when delicately measured explosives were being laid down, when a difficult seam was hit.”
   “In other words, during emergencies,” Powell was excited.
   “Right! When did you expect it to happen! It’s the personal initiative factor that’s giving us the trouble. And it’s just during emergencies in the absence of a human being that personal initiative is most strained. Now what is the logical deduction? How can we create our own stoppage when and where we want it?” He paused triumphantly—he was beginning to enjoy his role—and answered his own question to forestall the obvious answer on Powell’s tongue. “By creating our own emergency.”
   Powell said, “Mike—you’re right.”
   “Thanks, pal. I knew I’d do it some day.”
   “All right, and skip the sarcasm. We’ll save it for Earth, and preserve it in jars for future long, cold winters. Meanwhile, what emergency can we create?”
   “We could flood the mines, if this weren’t an airless asteroid.”
   “A witticism, no doubt,” said Powell. “Really, Mike, you’ll incapacitate me with laughter. What about a mild cave-in?”
   Donovan pursed his lips and said, “O.K. by me.”
   “Good. Let’s get started.”

  Powell felt uncommonly like a conspirator as he wound his way over the craggy landscape. His sub-gravity walk teetered across the broken ground, kicking rocks to right and left under his weight in noiseless puffs of gray dust. Mentally, though, it was the cautious crawl of the plotter.
   He said, “Do you know where they are?”
   “I think so, Greg.”
   “All right,” Powell said gloomily, “but if any ‘finger’ gets within twenty feet of us, we’ll be sensed whether we are in the line of sight or not. I hope you know that.”
   “When I need an elementary course in robotics, I’ll file an application with you formally, and in triplicate. Down through here.”
   They were in the tunnels now; even the starlight was gone. The two hugged the walls, flashes flickering out the way in intermittent bursts. Powell felt for the security of his detonator.
   “Do you know this tunnel, Mike?”
   “Not so good. It’s a new one. I think I can make it out from what I saw in the visiplate, though—”
   Interminable minutes passed, and then Mike said, “Feel that!”
   There was a slight vibration thrumming the wall against the fingers of Powell’s metal-incased hand. There was no sound, naturally.
   “Blasting! We’re pretty close.”
   “Keep your eyes open,” said Powell.
   Donovan nodded impatiently.
   It was upon them and gone before they could seize themselves—just a bronze glint across the field of vision. They clung together in silence.
   Powell whispered, “Think it sensed us?”
   “Hope not. But we’d better flank them. Take the first side tunnel to the right.”
   “Suppose we miss them altogether?”
   “Well what do you want to do? Go back?” Donovan grunted fiercely. “They’re within a quarter of a mile. I was watching them through the visiplate, wasn’t I? And we’ve got two days—”
   “Oh, shut up. You’re wasting your oxygen. Is this a side passage here?” The flash flicked. “It is. Let’s go.”
   The vibration was considerably more marked and the ground below shuddered uneasily.
   “This is good,” said Donovan, “if it doesn’t give out on us, though.” He flung his light ahead anxiously.
   They could touch the roof of the tunnel with a half-upstretched hand, and the bracings had been newly placed.
   Donovan hesitated, “Dead end, let’s go back.”
   “No. Hold on.” Powell squeezed clumsily past. “Is that light ahead?”
   “Light? I don’t see any. Where would there be light down here?”
   “Robot light.” He was scrambling up a gentle incline on hands and knees. His voice was hoarse and anxious in Donovan’s ears. “Hey, Mike, come up here.”
   There was light. Donovan crawled up and over Powell’s outstretched legs. “An opening?”
   “Yes. They must be working into this tunnel from the other side now I think.”
   Donovan felt the ragged edges of the opening that looked out into what the cautious flashlight showed to be a larger and obviously main stem tunnel. The hole was too small for a man to go through, almost too small for two men to look through simultaneously.
   There’s nothing there,” said Donovan.
   “Well, not now. But there must have been a second ago or we wouldn’t have seen light. Watch out!”
   The walls rolled about them and they felt the impact. A fine dust showered down. Powell lifted a cautious head and looked again. “All right, Mike. They’re there.”
   The glittering robots clustered fifty feet down the main stem. Metal arms labored mightily at the rubbish heap brought down by the last blast.
   Donovan urged eagerly, “Don’t waste time. It won’t be long before they get through, and the next blast may get us.”
   “For Pete’s sake, don’t rush me.” Powell unlimbered the detonator, and his eyes searched anxiously across the dusky background where the only light was robot light and it was impossible to tell a projecting boulder from a shadow.
   “There’s a spot in the roof, see it, almost over them. The last blast didn’t quite get it. If you can get it at the base, half the roof will cave in.”
   Powell followed the dim finger, “Check! Now fasten your eye on the robots and pray they don’t move too far from that part of the tunnel. They’re my light sources. Are all seven there?”
   Donovan counted, “All seven.”
   “Well, then, watch them. Watch every motion!”
   His detonator was lifted and remained poised while Donovan watched and cursed and blinked the sweat out of his eye.
   It flashed!
   There was a jar, a series of hard vibrations, and then a jarring thump that threw Powell heavily against Donovan.
   Donovan yowled, “Greg, you threw me off. I didn’t see a thing.”
   Powell stared about wildly, “Where are they?”
   Donovan fell into a stupid silence. There was no sign of the robots. It was dark as the depths of the River Styx.
   “Think we buried them?” quavered Donovan.
   “Let’s get down there. Don’t ask me what I think.” Powell crawled backward at tumbling speed.
   “Mike!”
   Donovan paused in the act of following. “What’s wrong now?”
   “Hold on!” Powell’s breathing was rough and irregular in Donovan’s ears. “Mike! Do you hear me, Mike?”
   “I’m right here. What is it?”
   “We’re blocked in. It wasn’t the ceiling coming down fifty feet away that knocked us over. It was our own ceiling. The shock’s tumbled it!”
   “What!” Donovan scrambled up against a hard barrier. “Turn on the flash.”
   Powell did so. At no point was there room for a rabbit to squeeze through.
   Donovan said softly, “Well, what do you know?”
   They wasted a few moments and some muscular power in an effort to move the blocking barrier. Powell varied this by wrenching at the edges of the original hole. For a moment, Powell lifted his blaster. But in those close quarters, a flash would be suicide and he knew it. He sat down.
   “You know, Mike,” he said, “we’ve really messed this up. We are no nearer finding out what’s wrong with Dave. It was a good idea but it blew up in our face.”
   Donovan’s glance was bitter with an intensity totally wasted on the darkness, “I hate to disturb you, old man, but quite apart from what we know or don’t know of Dave, we’re slightly trapped. If we don’t get loose, fella, we’re going to die. D-I-E, die. How much oxygen have we anyway? Not more than six hours.”
   “I’ve thought of that.” Powell’s fingers went up to his long-suffering mustache and clanged uselessly against the transparent visor. “Of course, we could get Dave to dig us out easily in that time, except that our precious emergency must have thrown him off, and his radio circuit is out.”
   “And isn’t that nice?”
   Donovan edged up to the opening and managed to get his metal incased head out. It was an extremely tight fit.
   “Hey, Greg!”
   “What?”
   “Suppose we get Dave within twenty feet. He’ll snap to normal. That will save us.”
   “Sure, but where is he?”
   “Down the corridor—way down. For Pete’s sake, stop pulling before you drag my head out of its socket. I’ll give you your chance to look.”
   Powell maneuvered his head outside, “We did it all right. Look at those saps. That must be a ballet they’re doing.”
   “Never mind the side remarks. Are they getting any closer?”
   “Can’t tell yet. They’re too far away. Give me a chance. Pass me my flash, will you? I’ll try to attract their attention that way.”
   He gave up after two minutes, “Not a chance! They must be blind. Uh-oh, they’re starting toward us. What do you know?”
   Donovan said, “Hey, let me see!”
   There was a silent scuffle. Powell said, “All right!” and Donovan got his head out.
   They were approaching. Dave was high-stepping the way in front and the six “fingers” were a weaving chorus line behind him.
   Donovan marveled, “What are they doing? That’s what I want to know. It looks like the Virginia reel—and Dave’s a major-domo, or I never saw one.”
   “Oh, leave me alone with your descriptions,” grumbled Powell. “How near are they?”
   “Within fifty feet and coming this way. We’ll be out in fifteen minUh-huh-HUH-HEY-Y!”
   “What’s going on?” It took Powell several seconds to recover from his stunned astonishment at Donovan’s vocal gyrations. “Come on, give me a chance at that hole. Don’t be a hog about it.”
   He fought his way upward, but Donovan kicked wildly, “They did an about-face, Greg. They’re leaving. Dave! Hey, Da-a ave!”
   Powell shrieked, “What’s the use of that, you fool? Sound won’t carry.”
   “Well, then,” panted Donovan, “kick the walls, slam them, get some vibration started. We’ve got to attract their attention somehow, Greg, or we’re through. “ He pounded like a madman.
   Powell shook him, “Wait, Mike, wait. Listen, I’ve got an idea. Jumping Jupiter, this is a fine time to get around to the simple solutions. Mike!”
   “What do you want?” Donovan pulled his head in.
   “Let me in there fast before they get out of range.”
   “Out of range! What are you going to do? Hey, what are you going to do with that detonator?” He grabbed Powell’s arm.
   Powell shook off the grip violently. “I’m going to do a little shooting.”
   “Why?”
   “That’s for later. Let’s see if it works first. If it doesn’t, then—Get out of the way and let me shoot!”
   The robots were flickers, small and getting smaller, in the distance. Powell lined up the sights tensely, and pulled the trigger three times. He lowered the guns and peered anxiously. One of the subsidiaries was down! There were only six gleaming figures now.
   Powell called into his transmitter uncertainly. “Dave!”
   A pause, then the answer sounded to both men, “Boss? Where are you? My third subsidiary has had his chest blown in. He’s out of commission.”
   “Never mind your subsidiary,” said Powell. “We’re trapped in a cave-in where you were blasting. Can you see our flashlight?”
   “Sure. We’ll be right there.”
   Powell sat back and relaxed, “That, my fran’, is that”
   Donovan said very softly with tears in his voice, “All right, Greg. You win. I beat my forehead against the ground before your feet. Now don’t feed me any bull. Just tell me quietly what it’s all about.”
   “Easy. It’s just that all through we missed the obvious—as usual. We knew it was the personal initiative circuit, and that it always happened during emergencies, but we kept looking for a specific order as the cause. Why should it be an order?”
   “Why not?”
   “Well, look, why not a type of order. What type of order requires the most initiative? What type of order would occur almost always only in an emergency?”
   “Don’t ask me, dreg. Tell me!”
   “I’m doing it! It’s the six-way order. Under all ordinary conditions, one or more of the ‘fingers’ would be doing routine tasks requiring no close supervision—in the sort of offhand way our bodies handle the routine walking motions. But in an emergency, all six subsidiaries must be mobilized immediately and simultaneously. Dave must handle six robots at a time and something gives. The rest was easy. Any decrease in initiative required, such as the arrival of humans, snaps him back. So I destroyed one of the robots. When I did, he was transmitting only five-way orders. Initiative decreases—he’s normal”
   “How did you get all that?” demanded Donovan.
   “Just logical guessing. I tried it and it worked.”

  The robot’s voice was in their ears again, “Here I am. Can you hold out half an hour?”
   “Easy!” said Powell. Then, to Donovan, he continued, “And now the job should be simple. We’ll go through the circuits, and check off each part that gets an extra workout in a six-way order as against a five-way. How big a field does that leave us?”
   Donovan considered, “Not much, I think. If Dave is like the preliminary model we saw back at the factory, there’s a special coordinating circuit that would be the only section involved.” He cheered up suddenly and amazingly, “Say, that wouldn’t be bad at all. There’s nothing to that.”
   “All right. You think it over and we’ll check the blueprints when we get back. And now, till Daves reaches us, I’m relaxing.”
   “Hey, wait! Just tell me one thing. What were those queer shifting marches, those funny dance steps, that the robots went through every time they went screwy?”
   “That? I don’t know. But I’ve got a notion. Remember, those subsidiaries were Dave’s ‘fingers.’ We were always saying that, you know. Well, it’s my idea that in all these interludes, whenever Dave became a psychiatric case, he went off into a moronic maze, spending his time twiddling his fingers.”
   Susan Calvin talked about Powell and Donovan with unsmiling amusement, but warmth came into her voice when she mentioned robots. It didn’t take her long to go through the Speedies, the Cuties and the Daves, and I stopped her. Otherwise, she would have dredged up half a dozen more.
   I said, “Doesn’t anything ever happen on Earth?”
   She looked at me with a little frown, “No, we don’t have much to do with robots in action here on Earth.”
   “Oh, well that’s too bad. I mean, your field-engineers are swell, but can’t we get you into this? Didn’t you ever have a robot go wrong on you? It’s your anniversary, you know.”
   And so help me she blushed. She said, “Robots have gone wrong on me. Heavens, how long it’s been since I thought of it. Why, it was almost forty years ago. Certainly! 2021! And I was only thirty-eight. Oh, my—I’d rather not talk about it.”
   I waited, and sure enough she changed her mind. “Why not?” she said. “It cannot harm me now. Even the memory can’t. I was foolish once, young man. Would you believe that?”
   “No,” I said.
   “I was. But Herbie was a mind-reading robot.”
   “What?”
   “Only one of its kind, before or since. A mistake,—somewheres—”

Liar!

   Alfred Lanning lit his cigar carefully, but the tips of his fingers were trembling slightly. His gray eyebrows hunched low as he spoke between puffs.
   “It reads minds all right-damn little doubt about that! But why?” He looked at Mathematician Peter Bogert, “Well?”
   Bogert flattened his black hair down with both hands, “That was the thirty-fourth RB model we’ve turned out, Lanning. All the others were strictly orthodox.”
   The third man at the table frowned. Milton Ashe was the youngest officer of U. S. Robot & Mechanical Men, Inc., and proud of his post.
   “Listen, Bogert. There wasn’t a hitch in the assembly from start to finish. I guarantee that.”
   Bogert’s thick lips spread in a patronizing smile, “Do you? If you can answer for the entire assembly line, I recommend your promotion. By exact count, there are seventy-five thousand, two hundred and thirty-four operations necessary for the manufacture of a single positronic brain, each separate operation depending for successful completion upon any number of factors, from five to a hundred and five. If any one of them goes seriously wrong, the ‘brain’ is ruined. I quote our own information folder, Ashe.”
   Milton Ashe flushed, but a fourth voice cut off his reply.
   “If we’re going to start by trying to fix the blame on one another, I’m leaving.” Susan Calvin’s hands were folded tightly in her lap, and the little lines about her thin, pale lips deepened, “We’ve got a mind-reading robot on our hands and it strikes me as rather important that we find out just why it reads minds. We’re not going to do that by saying, ‘Your fault! My fault!’ “
   Her cold gray eyes fastened upon Ashe, and he grinned.
   Lanning grinned too, and, as always at such times, his long white hair and shrewd little eyes made him the picture of a biblical patriarch, “True for you, Dr. Calvin.”
   His voice became suddenly crisp, “Here’s everything in pill-concentrate form. We’ve produced a positronic brain of supposedly ordinary vintage that’s got the remarkable property of being able to tune in on thought waves. It would mark the most important advance in robotics in decades, if we knew how it happened. We don’t, and we have to find out. Is that clear?”
   “May I make a suggestion?” asked Bogert.
   “Go ahead!”
   “I’d say that until we do figure out the mess—and as a mathematician I expect it to be a very devil of a mess—we keep the existence of RD-34 a secret. I mean even from the other members of the staff. As heads of the departments, we ought not to find it an insoluble problem, and the fewer know about it—”
   “Bogert is right,” said Dr. Calvin. “Ever since the Interplanetary Code was modified to allow robot models to be tested in the plants before being shipped out to space, antirobot propaganda has increased. If any word leaks out about a robot being able to read minds before we can announce complete control of the phenomenon, pretty effective capital could be made out of it.”
   Lanning sucked at his cigar and nodded gravely. He turned to Ashe; “I think you said you were alone when you first stumbled on this thought-reading business.”
   “I’ll say I was alone—I got the scare of my life. RB-34 had just been taken off the assembly table and they sent him down to me. Obermann was off somewheres, so I took him down to the testing rooms myself—at least I started to take him down.” Ashe paused, and a tiny smile tugged at his lips, “Say, did any of you ever carry on a thought conversation without knowing it?”
   No one bothered to answer, and he continued, “You don’t realize it at first, you know. He just spoke to me—as logically and sensibly as you can imagine—and it was only when I was most of the way down to the testing rooms that I realized that I hadn’t said anything. Sure, I thought lots, but that isn’t the same thing, is it? I locked that thing up and ran for Lanning. Having it walking beside me, calmly peering into my thoughts and picking and choosing among them gave me the willies.”
   “I imagine it would,” said Susan Calvin thoughtfully. Her eyes fixed themselves upon Ashe in an oddly intent manner. “We are so accustomed to considering our own thoughts private.”
   Lanning broke in impatiently, “Then only the four of us know. All right! We’ve got to go about this systematically. Ashe, I want you to check over the assembly line from beginning to end—everything. You’re to eliminate all operations in which there was no possible chance of an error, and list all those where there were, together with its nature and possible magnitude.”
   “Tall order,” grunted Ashe.
   “Naturally! Of course, you’re to put the men under you to work on this—every single one if you have to, and I don’t care if we go behind schedule, either. But they’re not to know why, you understand.”
   “Hm-m-m, yes!” The young technician grinned wryly. “It’s still a lulu of a job.”
   Lanning swiveled about in his chair and faced Calvin, “You’ll have to tackle the job from the other direction. You’re the robo-psychologist of the plant, so you’re to study the robot itself and work backward. Try to find out how he ticks. See what else is tied up with his telepathic powers, how far they extend, how they warp his outlook, and just exactly what harm it has done to his ordinary RB properties. You’ve got that?”
   Lanning didn’t wait for Dr. Calvin to answer.
   “I’ll co-ordinate the work and interpret the findings mathematically.” He puffed violently at his cigar and mumbled the rest through the smoke; “Bogert will help me there, of course.”
   Bogert polished the nails of one pudgy hand with the other and said blandly, “I dare say. I know a little in the line.”
   “Well! I’ll get started.” Ashe shoved his chair back and rose. His pleasantly youthful face crinkled in a grin, “I’ve got the darnedest job of any of us, so I’m getting out of here and to work.”
   He left with a slurred, “B’ seein’ ye!”
   Susan Calvin answered with a barely perceptible nod, but her eyes followed him out of sight and she did not answer when Lanning grunted and said, “Do you want to go up and see RB-34 now, Dr. Calvin?”
   RB-34’s photoelectric eyes lifted from the book at the muffled sound of binges turning and he was upon his feet when Susan Calvin entered.
   She paused to readjust the huge “No Entrance” sign upon the door and then approached the robot.
   “I’ve brought you the texts upon hyperatomic motors, Herbie—a few anyway. Would you care to look at them?”
   RB-34—otherwise known as Herbie—lifted the three heavy books from her arms and opened to the title page of one:
   “Hm-m-m! ‘Theory of Hyperatomics.’ “ He mumbled inarticulately to himself as he flipped the pages and then spoke with an abstracted air, “Sit down, Dr. Calvin! This will take me a few minutes.”
   The psychologist seated herself and watched Herbie narrowly as he took a chair at the other side of the table and went through the three books systematically.
   At the end of half an hour, he put them down, “Of course, I know why you brought these.”
   The corner of Dr. Calvin’s lip twitched, “I was afraid you would. It’s difficult to work with you, Herbie. You’re always a step ahead of me.”
   “It’s the same with these books, you know, as with the others. They just don’t interest me. There’s nothing to your textbooks. Your science is just a mass of collected data plastered together by makeshift theory—and all so incredibly simple, that it’s scarcely worth bothering about.
   “It’s your fiction that interests me. Your studies of the interplay of human motives and emotions”—his mighty hand gestured vaguely as he sought the proper words.
   Dr. Calvin whispered, “I think I understand.”
   “I see into minds, you see,” the robot continued, “and you have no idea how complicated they are. I can’t begin to understand everything because my own mind has so little in common with them—but I try, and your novels help.”
   “Yes, but I’m afraid that after going through some of the harrowing emotional experiences of our present-day sentimental novel”—there was a tinge of bitterness in her voice—“you find real minds like ours dull and colorless.”
   “But I don’t!”

  The sudden energy in the response brought the other to her feet. She felt herself reddening, and thought wildly, “He must know!”
   Herbie subsided suddenly, and muttered in a low voice from which the metallic timbre departed almost entirely. “But, of course, I know about it, Dr. Calvin. You think of it always, so how can I help but know?”
   Her face was hard. “Have you—told anyone?”
   “Of course not!” This, with genuine surprise, “No one has asked me.”
   “Well, then,” she flung out, “I suppose you think I am a fool.”
   “No! It is a normal emotion.”
   “Perhaps that is why it is so foolish.” The wistfulness in her voice drowned out everything else. Some of the woman peered through the layer of doctorhood. “I am not what you would call—attractive.”
   “If you are referring to mere physical attraction, I couldn’t judge. But I know, in any case, that there are other types of attraction.”
   “Nor young.” Dr. Calvin had scarcely heard the robot.
   “You are not yet forty.” An anxious insistence had crept into Herbie’s voice.
   “Thirty-eight as you count the years; a shriveled sixty as far as my emotional outlook on life is concerned. Am I a psychologist for nothing?”
   She drove on with bitter breathlessness, “And he’s barely thirty-five and looks and acts younger. Do you suppose he ever sees me as anything but … but what I am?”
   “You are wrong!” Herbie’s steel fist struck the plastic-topped table with a strident clang. “Listen to me—”
   But Susan Calvin whirled on him now and the hunted pain in her eyes became a blaze, “Why should I? What do you know about it all, anyway, you … you machine. I’m just a specimen to you; an interesting bug with a peculiar mind spread-eagled for inspection. It’s a wonderful example of frustration, isn’t it? Almost as good as your books.” Her voice, emerging in dry sobs, choked into silence.
   The robot cowered at the outburst. He shook his head pleadingly. “Won’t you listen to me, please? I could help you if you would let me.”
   “How?” Her lips curled. “By giving me good advice?”
   “No, not that. It’s just that I know what other people think—Milton Ashe, for instance.”
   There was a long silence, and Susan Calvin’s eyes dropped. “I don’t want to know what he thinks,” she gasped. “Keep quiet.”
   “I think you would want to know what he thinks”
   Her head remained bent, but her breath came more quickly. “You are talking nonsense,” she whispered.
   “Why should I? I am trying to help. Milton Ashe’s thoughts of you—” he paused.
   And then the psychologist raised her head, “Well?”
   The robot said quietly, “He loves you.”
   For a full minute, Dr. Calvin did not speak. She merely stared. Then, “You are mistaken! You must be. Why should he?”
   “But he does. A thing like that cannot be hidden, not from me.”
   “But I am so … so—” she stammered to a halt.
   “He looks deeper than the skin, and admires intellect in others. Milton Ashe is not the type to marry a head of hair and a pair of eyes.”
   Susan Calvin found herself blinking rapidly and waited before speaking. Even then her voice trembled, “Yet he certainly never in any way indicated—”
   “Have you ever given him a chance?”
   “How could I? I never thought that—”
   “Exactly!”
   The psychologist paused in thought and then looked up suddenly. “A girl visited him here at the plant half a year ago. She was pretty, I suppose—blond and slim. And, of course, could scarcely add two and two. He spent all day puffing out his chest, trying to explain how a robot was put together.” The hardness had returned, “Not that she understood! Who was she?”
   Herbie answered without hesitation, “I know the person you are referring to. She is his first cousin, and there is no romantic interest there, I assure you.”
   Susan Calvin rose to her feet with a vivacity almost girlish. “Now isn’t that strange? That’s exactly what I used to pretend to myself sometimes, though I never really thought so. Then it all must be true.”
   She ran to Herbie and seized his cold, heavy hand in both hers. “Thank you, Herbie.” Her voice was an urgent, husky whisper. “Don’t tell anyone about this. Let it be our secret—and thank you again.” With that, and a convulsive squeeze of Herbie’s unresponsive metal fingers, she left.
   Herbie turned slowly to his neglected novel, but there was no one to read his thoughts.
   Milton Ashe stretched slowly and magnificently, to the tune of cracking joints and a chorus of grunts, and then glared at Peter Bogert, Ph.D.
   “Say,” he said, “I’ve been at this for a week now with just about no sleep. How long do I have to keep it up? I thought you said the positronic bombardment in Vac Chamber D was the solution.”
   Bogert yawned delicately and regarded his white hands with interest. “It is. I’m on the track.”
   “I know what that means when a mathematician says it. How near the end are you?”
   “It all depends.”
   “On what?” Ashe dropped into a chair and stretched his long legs out before him.
   “On Lanning. The old fellow disagrees with me.” He sighed, “A bit behind the times, that’s the trouble with him. He clings to matrix mechanics as the all in all, and this problem calls for more powerful mathematical tools. He’s so stubborn.”
   Ashe muttered sleepily, “Why not ask Herbie and settle the whole affair?”
   “Ask the robot?” Bogert’s eyebrows climbed.
   “Why not? Didn’t the old girl tell you?”
   “You mean Calvin?”
   “Yeah! Susie herself. That robot’s a mathematical wiz. He knows all about everything plus a bit on the side. He does triple integrals in his head and eats up tensor analysis for dessert.”
   The mathematician stared skeptically, “Are you serious?”
   “So help me! The catch is that the dope doesn’t like math. He would rather read slushy novels. Honest! You should see the tripe Susie keeps feeding him: ‘Purple Passion’ and ‘Love in Space.’ “
   “Dr. Calvin hasn’t said a word of this to us.”
   “Well, she hasn’t finished studying him. You know how she is. She likes to have everything just so before letting out the big secret.”
   “She’s told you.”
   “We sort of got to talking. I have been seeing a lot of her lately.” He opened his eyes wide and frowned, “Say, Bogie, have you been noticing anything queer about the lady lately?”

   Bogert relaxed into an undignified grin, “She’s using lipstick, if that’s what you mean.”
   “Hell, I know that. Rouge, powder and eye shadow, too. She’s a sight. But it’s not that. I can’t put my finger on it. It’s the way she talks—as if she were happy about something.” He thought a little, and then shrugged.
   The other allowed himself a leer, which, for a scientist past fifty, was not a bad job, “Maybe she’s in love.”
   Ashe allowed his eyes to close again, “You’re nuts, Bogie. You go speak to Herbie; I want to stay here and go to sleep.”
   “Right! Not that I particularly like having a robot tell me my job, nor that I think he can do it!”
   A soft snore was his only answer.
   Herbie listened carefully as Peter Bogert, hands in pockets, spoke with elaborate indifference.
   “So there you are. I’ve been told you understand these things, and I am asking you more in curiosity than anything else. My line of reasoning, as I have outlined it, involves a few doubtful steps, I admit, which Dr. Lanning refuses to accept, and the picture is still rather incomplete.”
   The robot didn’t answer, and Bogert said, “Well?”
   “I see no mistake,” Herbie studied the scribbled figures.
   “I don’t suppose you can go any further than that?”
   “I daren’t try. You are a better mathematician than I, and—well, I’d hate to commit myself.”
   There was a shade of complacency in Bogert’s smile, “I rather thought that would be the case. It is deep. We’ll forget it.” He crumpled the sheets, tossed them down the waste shaft, turned to leave, and then thought better of it.
   “By the way—”
   The robot waited.
   Bogert seemed to have difficulty. “There is something—that is, perhaps you can—“ He stopped.
   Herbie spoke quietly. “Your thoughts are confused, but there is no doubt at all that they concern Dr. Lanning. It is silly to hesitate, for as soon as you compose yourself, I’ll know what it is you want to ask.”
   The mathematician’s hand went to his sleek hair in the familiar smoothing gesture. “Lanning is nudging seventy,” he said, as if that explained everything.
   “I know that.”
   “And he’s been director of the plant for almost thirty years.” Herbie nodded.
   “Well, now,” Bogert’s voice became ingratiating, “you would know whether … whether he’s thinking of resigning. Health, perhaps, or some other—”
   “Quite,” said Herbie, and that was all.
   “Well, do you know?”
   “Certainly.”
   “Then-uh-could you tell me?”
   “Since you ask, yes.” The robot was quite matter-of-fact about it. “He has already resigned!”
   “What!” The exclamation was an explosive, almost inarticulate, sound. The scientist’s large head hunched forward, “Say that again!”
   “He has already resigned,” came the quiet repetition, “but it has not yet taken effect. He is waiting, you see, to solve the problem of—er—myself. That finished, he is quite ready to turn the office of director over to his successor.”
   Bogert expelled his breath sharply, “And this successor? Who is he?” He was quite close to Herbie now, eyes fixed fascinatedly on those unreadable dull-red photoelectric cells that were the robot’s eyes.
   Words came slowly, “You are the next director.”
   And Bogert relaxed into a tight smile, “This is good to know. I’ve been hoping and waiting for this. Thanks, Herbie.”
   Peter Bogert was at his desk until five that morning and he was back at nine. The shelf just over the desk emptied of its row of reference books and tables, as he referred to one after the other. The pages of calculations before him increased microscopically and the crumpled sheets at his feet mounted into a hill of scribbled paper.
   At precisely noon, he stared at the final page, rubbed a blood-shot eye, yawned and shrugged. “This is getting worse each minute. Damn!”
   He turned at the sound of the opening door and nodded at Lanning, who entered, cracking the knuckles of one gnarled hand with the other.
   The director took in the disorder of the room and his eyebrows furrowed together.
   “New lead?” he asked.
   “No,” came the defiant answer. “What’s wrong with the old one?”
   Lanning did not trouble to answer, nor to do more than bestow a single cursory glance at the top sheet upon Bogert’s desk. He spoke through the flare of a match as he lit a cigar.
   “Has Calvin told you about the robot? It’s a mathematical genius. Really remarkable.”
   The other snorted loudly, “So I’ve heard. But Calvin had better stick to robopsychology. I’ve checked Herbie on math, and he can scarcely struggle through calculus.”
   “Calvin didn’t find it so.”
   “She’s crazy.”
   “And I don’t find it so.” The director’s eyes narrowed dangerously.
   “You!” Bogert’s voice hardened. “What are you talking about?”
   “I’ve been putting Herbie through his paces all morning, and he can do tricks you never heard of.”
   “Is that so?”
   “You sound skeptical!” Lanning flipped a sheet of paper out of his vest pocket and unfolded it. “That’s not my handwriting, is it?”
   Bogert studied the large angular notation covering the sheet, “Herbie did this?”
   “Right! And if you’ll notice, he’s been working on your time integration of Equation 22. It comes”—Lanning tapped a yellow fingernail upon the last step—“to the identical conclusion I did, and in a quarter the time. You had no right to neglect the Linger Effect in positronic bombardment.”
   “I didn’t neglect it. For Heaven’s sake, Lanning, get it through your head that it would cancel out—”
   “Oh, sure, you explained that. You used the Mitchell Translation Equation, didn’t you? Well—it doesn’t apply.”
   “Why not?”
   “Because you’ve been using hyper-imaginaries, for one thing.”
   “What’s that to do with?”
   “Mitchell’s Equation won’t hold when—”
   “Are you crazy? If you’ll reread Mitchell’s original paper in the Transactions of the Far—”
   “I don’t have to. I told you in the beginning that I didn’t like his reasoning, and Herbie backs me in that.”
   “Well, then,” Bogert shouted, “let that clockwork contraption solve the entire problem for you. Why bother with nonessentials?”
   “That’s exactly the point. Herbie can’t solve the problem. And if he can’t, we can’t—alone. I’m submitting the entire question to the National Board. It’s gotten beyond us.”
   Bogert’s chair went over backward as he jumped up a-snarl, face crimson. “You’re doing nothing of the sort.”

   Lanning flushed in his turn, “Are you telling me what I can’t do?”
   “Exactly,” was the gritted response. “I’ve got the problem beaten and you’re not to take it out of my hands, understand? Don’t think I don’t see through you, you desiccated fossil. You’d cut your own nose off before you’d let me get the credit for solving robotic telepathy.”
   “You’re a damned idiot, Bogert, and in one second I’ll have you suspended for insubordination”—Lanning’s lower lip trembled with passion.
   “Which is one thing you won’t do, Lanning. You haven’t any secrets with a mind-reading robot around, so don’t forget that I know all about your resignation.”
   The ash on Lanning’s cigar trembled and fell, and the cigar itself followed, “What … what—”
   Bogert chuckled nastily, “And I’m the new director, be it understood. I’m very aware of that, don’t think I’m not. Damn your eyes, Lanning, I’m going to give the orders about here or there will be the sweetest mess that you’ve ever been in.”
   Lanning found his voice and let it out with a roar. “You’re suspended, d’ye hear? You’re relieved of all duties. You’re broken, do you understand?”
   The smile on the other’s face broadened, “Now, what’s the use of that? You’re getting nowhere. I’m holding the trumps. I know you’ve resigned. Herbie told me, and he got it straight from you.”
   Lanning forced himself to speak quietly. He looked an old, old man, with tired eyes peering from a face in which the red had disappeared, leaving the pasty yellow of age behind, “I want to speak to Herbie. He can’t have told you anything of the sort. You’re playing a deep game, Bogert, but I’m calling your bluff. Come with me.”
   Bogert shrugged, “To see Herbie? Good! Damned good!”
   It was also precisely at noon that Milton Ashe looked up from his clumsy sketch and said, “You get the idea? I’m not too good at getting this down, but that’s about how it looks. It’s a honey of a house, and I can get it for next to nothing.”
   Susan Calvin gazed across at him with melting eyes. “It’s really beautiful,” she sighed. “I’ve often thought that I’d like to—” Her voice trailed away.
   “Of course,” Ashe continued briskly, putting away his pencil, “I’ve got to wait for my vacation. It’s only two weeks off, but this Herbie business has everything up in the air.” His eyes dropped to his fingernails, “Besides, there’s another point—but it’s a secret.”
   “Then don’t tell me.”
   “Oh, I’d just as soon, I’m just busting to tell someone—and you’re just about the best—er—confidante I could find here.” He grinned sheepishly.
   Susan Calvin’s heart bounded, but she did not trust herself to speak.
   “Frankly,” Ashe scraped his chair closer and lowered his voice into a confidential whisper, “the house isn’t to be only for myself. I’m getting married!”
   And then he jumped out of his seat, “What’s the matter?”
   “Nothing!” The horrible spinning sensation had vanished, but it was hard to get words out. “Married? You mean—”
   “Why, sure! About time, isn’t it? You remember that girl who was here last summer. That’s she! But you are sick. You—”
   “Headache!” Susan Calvin motioned him away weakly. “I’ve … I’ve been subject to them lately. I want to … to congratulate you, of course. I’m very glad—” The inexpertly applied rouge made a pair of nasty red splotches upon her chalk-white face. Things had begun spinning again. “Pardon me—please—”
   The words were a mumble, as she stumbled blindly out the door. It had happened with the sudden catastrophe of a dream—and with all the unreal horror of a dream.
   But how could it be? Herbie had said-
   And Herbie knew! He could see into minds!
   She found herself leaning breathlessly against the doorjamb, staring into Herbie’s metal face. She must have climbed the two flights of stairs, but she had no memory of it. The distance had been covered in an instant, as in a dream.
   As in a dream!
   And still Herbie’s unblinking eyes stared into hers and their dull red seemed to expand into dimly shining nightmarish globes.
   He was speaking, and she felt the cold glass pressing against her lips. She swallowed and shuddered into a pertain awareness of her surroundings.
   Still Herbie spoke, and there was agitation in his voice—as if he were hurt and frightened and pleading.
   The words were beginning to make sense. “This is a dream,” he was saying, “and you mustn’t believe in it. You’ll wake into the real world soon and laugh at yourself. He loves you, I tell you. He does, he does! But not here! Not now! This is an illusion.”
   Susan Calvin nodded, her voice a whisper, “Yes! Yes!” She was clutching Herbie’s arm, clinging to it, repeating over and over, “It isn’t true, is it? It isn’t, is it?”
   Just how she came to her senses, she never knew—but it was like passing from a world of misty unreality to one of harsh sunlight. She pushed him away from her, pushed hard against that steely arm, and her eyes were wide.
   “What are you trying to do?” Her voice rose to a harsh scream. “What are you trying to do?”
   Herbie backed away, “I want to help”
   The psychologist stared, “Help? By telling me this is a dream? By trying to push me into schizophrenia?” A hysterical tenseness seized her, “This is no dream! I wish it were!”
   She drew her breath sharply, “Wait! Why … why, I understand. Merciful Heavens, it’s so obvious.”
   There was horror in the robot’s voice, “I had to!”
   “And I believed you! I never thought—”
   Loud voices outside the door brought her to a halt. She turned away, fists clenching spasmodically, and when Bogert and Lanning entered, she was at the far window. Neither of the men paid her the slightest attention.
   They approached Herbie simultaneously; Lanning angry and impatient, Bogert, coolly sardonic. The director spoke first.
   “Here now, Herbie. Listen to me!”
   The robot brought his eyes sharply down upon the aged director, “Yes, Dr. Lanning.”
   “Have you discussed me with Dr. Bogert?”
   “No, sir.” The answer came slowly, and the smile on Bogert’s face flashed off.
   “What’s that?” Bogert shoved in ahead of his superior and straddled the ground before the robot. “Repeat what you told me yesterday.”
   “I said that “ Herbie fell silent. Deep within him his metallic diaphragm vibrated in soft discords.
   “Didn’t you say he had resigned?” roared Bogert. “Answer me!”
   Bogert raised his arm frantically, but Lanning pushed him aside, “Are you trying to bully him into lying?”
   “You heard him, Lanning. He began to say ‘Yes’ and stopped. Get out of my way! I want the truth out of him, understand!”
   “I’ll ask him!” Lanning turned to the robot. “All right, Herbie, take it easy. Have I resigned?”
   Herbie stared, and Lanning repeated anxiously, “Have I resigned?” There was the faintest trace of a negative shake of the robot’s head. A long wait produced nothing further.
   The two men looked at each other and the hostility in their eyes was all but tangible.
   “What the devil,” blurted Bogert, “has the robot gone mute? Can’t you speak, you monstrosity?”
   “I can speak,” came the ready answer.
   “Then answer the question. Didn’t you tell me Lanning had resigned? Hasn’t he resigned?”
   And again there was nothing but dull silence, until from the end of the room Susan Calvin’s laugh rang out suddenly, high-pitched and semi-hysterical.
   The two mathematicians jumped, and Bogerts eyes narrowed, “You here? What’s so funny?”
   “Nothing’s funny.” Her voice was not quite natural. “It’s just that I’m not the only one that’s been caught. There’s irony in three of the greatest experts in robotics in the world falling into the same elementary trap, isn’t there?” Her voice faded, and she put a pale hand to her forehead, “But it isn’t funny!”
   This time the look that passed between the two men was one of raised eyebrows. “What trap are you talking about?” asked Lansing stiffly. “Is something wrong with Herbie?”
   “No,” she approached them slowly, “nothing is wrong with him—only with us.” She whirled suddenly and shrieked at the robot, “Get away from me! Go to the other end of the room and don’t let me look at you.”
   Herbie cringed before the fury of her eyes and stumbled away in a clattering trot.
   Lanning’s voice was hostile, “What is all this, Dr. Calvin?”
   She faced them and spoke sarcastically, “Surely you know the fundamental First Law of Robotics.”
   The other two nodded together. “Certainly,” said Bogert, Irritably, “a robot may not injure a human being or, through inaction, allow him to come to harm”
   “How nicely put,” sneered Calvin. “But what kind of harm?”
   “Why—any kind.”
   “Exactly! Any kind! But what about hurt feelings? What about deflation of one’s ego? What about the blasting of one’s hopes? Is that injury?”
   Lanning frowned, “What would a robot know about—” And then he caught himself with a gasp.
   “You’ve caught on, have you? This robot reads minds. Do you suppose it doesn’t know everything about mental injury? Do you suppose that if asked a question, it wouldn’t give exactly that answer that one wants to hear? Wouldn’t any other answer hurt us, and wouldn’t Herbie know that?”
   “Good Heavens!” muttered Bogert.
   The psychologist cast a sardonic glance at him, “I take it you asked him whether Lanning had resigned. You wanted to hear that he had resigned and so that’s what Herbie told you.”
   “And I suppose that is why,” said Lanning, tonelessly, “it would not answer a little while ago. It couldn’t answer either way without hurting one of us.”
   There was a short pause in which the men looked thoughtfully across the room at the robot, crouching in the chair by the bookcase, head resting in one hand.
   Susan Calvin stared steadfastly at the floor, “He knew of all this. That … that devil knows everything—including what went wrong in his assembly.” Her eyes were dark and brooding.
   Lanning looked up, “You’re wrong there, Dr. Calvin. He doesn’t know what went wrong. I asked him.”
   “What does that mean?” cried Calvin. “Only that you didn’t want him to give you the solution. It would puncture your ego to have a machine do what you couldn’t. Did you ask him?” she shot at Bogert.
   “In a way.” Bogert coughed and reddened. “He told me he knew very little about mathematics.”
   Lanning laughed, not very loudly and the psychologist smiled caustically. She said, “I’ll ask him! A solution by him won’t hurt my ego” She raised her voice into a cold, imperative, “Come here!”
   Herbie rose and approached with hesitant steps.
   “You know, I suppose,” she continued, “just exactly at what point in the assembly an extraneous factor was introduced or an essential one left out.”
   “Yes,” said Herbie, in tones barely heard.
   “Hold on,” broke in Bogert angrily. “That’s not necessary true. You want to hear that, that’s all.”
   “Don’t be a fool,” replied Calvin. “He certainly knows as much math as you and Lanning together, since he can read minds. Give him his chance.”
   The mathematician subsided, and Calvin continued, “All right, then, Herbie, give! We’re waiting.” And in an aside, “Get pencils and paper, gentlemen.”
   But Herbie remained silent, and there was triumph in the psychologist’s voice, “Why don’t you answer, Herbie?”
   The robot blurted out suddenly, “I cannot. You know I cannot! Dr. Bogert and Dr. Lanning don’t want me to.”
   “They want the solution.”
   “But not from me.”

   Lanning broke in, speaking slowly and distinctly, “Don’t be foolish, Herbie. We do want you to tell us.”
   Bogert nodded curtly.
   Herbie’s voice rose to wild heights, “What’s the use of saying that? Don’t you suppose that I can see past the superficial skin of your mind? Down below, you don’t want me to. I’m a machine, given the imitation of life only by virtue of the positronic interplay in my brain—which is man’s device. You can’t lose face to me without being hurt. That is deep in your mind and won’t be erased. I can’t give the solution.”
   “We’ll leave,” said Dr. Lanning. “Tell Calvin.”
   “That would make no difference,” cried Herbie, “since you would know anyway that it was I that was supplying the answer.”
   Calvin resumed, “But you understand, Herbie, that despite that, Drs. Lanning and Bogert want that solution.”
   “By their own efforts!” insisted Herbie.
   “But they want it, and the fact that you have it and won’t give it hurts them. You see that, don’t you?”
   “Yes! Yes!”
   “And if you tell them that will hurt them, too”
   “Yes! Yes!” Herbie was retreating slowly, and step-by-step Susan Calvin advanced. The two men watched in frozen bewilderment.
   “You can’t tell them,” droned the psychologist slowly, “because that would hurt and you mustn’t hurt. But if you don’t tell them, you hurt, so you must tell them. And if you do, you will hurt and you mustn’t, so you can’t tell them; but if you don’t, you hurt, so you must; but if you do, you hurt, so you mustn’t; but if you don’t, you hurt, so you must; but if you do, you—”
   Herbie was up against the wall, and here he dropped to his knees. “Stop!” he shrieked. “Close your mind! It is full of pain and frustration and hate! I didn’t mean it, I tell you! I tried to help! I told you what you wanted to hear. I had to!”
   The psychologist paid no attention. “You must tell them, but if you do, you hurt, so you mustn’t; but if you don’t, you hurt, so you must; but—”
   And Herbie screamed!
   It was like the whistling of a piccolo many times magnified—shrill and shriller till it keened with the terror of a lost soul and filled the room with the piercingness of itself.
   And when it died into nothingness, Herbie collapsed into a huddled heap of motionless metal.
   Bogert’s face was bloodless, “He’s dead!”
   “No!” Susan Calvin burst into body-racking gusts of wild laughter, “not dead—merely insane. I confronted him with the insoluble dilemma, and he broke down. You can scrap him now—because he’ll never speak again.”
   Lanning was on his knees beside the thing that had been Herbie. His fingers touched the cold, unresponsive metal face and he shuddered. “You did that on purpose.” He rose and faced her, face contorted.
   “What if I did? You can’t help it now.” And in a sudden access of bitterness, “He deserved it.”
   The director seized the paralyzed, motionless Bogert by the wrist, “What’s the difference. Come, Peter.” He sighed, “A thinking robot of this type is worthless anyway.” His eyes were old and tired, and he repeated, “Come, Peter!”
   It was minutes after the two scientists left that Dr. Susan Calvin regained part of her mental equilibrium. Slowly, her eyes turned to the living-dead Herbie and the tightness returned to her face. Long she stared while the triumph faded and the helpless frustration returned—and of all her turbulent thoughts only one infinitely bitter word passed her lips.
   “Liar!”
   –
   That finished it for then, naturally. I knew I couldn’t get any more out of her after that. She just sat there behind her desk, her white face cold and—remembering.
   I said, “Thank you, Dr. Calvin!” but she didn’t answer. It was two days before I could get to see her again.

Little Lost Robot

   When I did see Susan Calvin again, it was at the door of her office. Files were being moved out.
   She said, “How are your articles coming along, young man?”
   “Fine,” I said. I had put them into shape according to my own lights, dramatized the bare bones of her recital, added the conversation and little touches, “Would you look over them and see if I haven’t been libelous or too unreasonably inaccurate anywhere?”
   “I suppose so. Shall we retire to the Executives’ Lounge? We can have coffee.”
   She seemed in good humor, so I chanced it as we walked down the corridor, “I was wondering, Dr. Calvin—”
   “Yes?”
   “If you would tell me more concerning the history of robotics.”
   “Surely you have what you want, young man.”
   “In a way. But these incidents I have written up don’t apply much to the modern world. I mean, there was only one mind-reading robot ever developed, and Space-Stations are already outmoded and in disuse, and robot mining is taken for granted. What about interstellar travel? It’s only been about twenty years since the hyperatomic motor was invented and it’s well known that it was a robotic invention. What is the truth about it?”
   “Interstellar travel?” She was thoughtful. We were in the lounge, and I ordered a full dinner. She just had coffee.
   “It wasn’t a simple robotic invention, you know; not just like that. But, of course, until we developed the Brain, we didn’t get very far. But we tried; we really tried. My first connection (directly, that is) with interstellar research was in 2029, when a robot was lost—”
   Measures on Hyper Base had been taken in a sort of rattling fury—the muscular equivalent of a hysterical shriek.
   To itemize them in order of both chronology and desperation, they were:
   All work on the Hyperatomic Drive through all the space volume occupied by the Stations of the Twenty-Seventh Asteroidal Grouping came to a halt.
   That entire volume of space was nipped out of the System, practically speaking. No one entered without permission. No one left under any conditions.
   By special government patrol ship, Drs. Susan Calvin and Peter Bogert, respectively Head Psychologist and Mathematical Director of United States Robot & Mechanical Men Corporation, were brought to Hyper Base.
   Susan Calvin had never left the surface of Earth before, and had no perceptible desire to leave it this time. In an age of Atomic Power and a clearly coming Hyperatomic Drive, she remained quietly provincial. So she was dissatisfied with her trip and unconvinced of the emergency, and every line of her plain, middle-aged face showed it clearly enough during her first dinner at Hyper Base.
   Nor did Dr. Bogert’s sleek paleness abandon a certain hangdog attitude. Nor did Major-general Kallner, who headed the project, even once forget to maintain a hunted expression. In short, it was a grisly episode, that meal, and the little session of three that followed began in a gray, unhappy manner.
   Kallner, with his baldness glistening, and his dress uniform oddly unsuited to the general mood, began with uneasy directness.
   “This is a queer story to tell, sir, and madam. I want to thank you for coming on short notice and without a reason being given. We’ll try to correct that now. We’ve lost a robot. Work has stopped and must stop until such time as we locate it. So far we have failed, and we feel we need expert help.”
   Perhaps the general felt his predicament anticlimactic. He continued with a note of desperation, “I needn’t tell you the importance of our work here. More than eighty percent of last year’s appropriations for scientific research have gone to us—”
   “Why, we know that,” said Bogert, agreeably. “U. S. Robots is receiving a generous rental fee for use of our robots.”
   Susan Calvin injected a blunt, vinegary note, “What makes a single robot so important to the project, and why hasn’t it been located?”
   The general turned his red face toward her and wet his lips quickly, “Why, in a manner of speaking we have located it.” Then, with near anguish, “Here, suppose I explain. As soon as the robot failed to report a state of emergency was declared, and all movement off Hyper Base stopped. A cargo vessel had landed the previous day and had delivered us two robots for our laboratories. It had sixty-two robots of the … uh … game type for shipment elsewhere. We are certain as to that figure. There is no question about it whatever.”
   “Yes? And the connection?”
   “When our missing robot failed of location anywhere—I assure you we would have found a missing blade of grass if it had been there to find—we brainstormed ourselves into counting the robots left of the cargo ship. They have sixty-three now.”
   “So that the sixty-third, I take it, is the missing prodigal?” Dr. Calvin’s eyes darkened.
   “Yes, but we have no way of telling which is the sixty-third.”
   There was a dead silence while the electric clock chimed eleven times, and then the robopsychologist said, “Very peculiar,” and the corners of her lips moved downward.
   “Peter,” she turned to her colleague with a trace of savagery, “what’s wrong here? What kind of robots are they, using at Hyper Base?”
   Dr. Bogert hesitated and smiled feebly, “It’s been rather a matter of delicacy till now, Susan.”
   She spoke rapidly, “Yes, till now. If there are sixty-three same-type robots, one of which is wanted and the identity of which cannot be determined, why won’t any of them do? What’s the idea of all this? Why have we been sent for?”
   Bogert said in resigned fashion, “If you’ll give me a chance, Susan—Hyper Base happens to be using several robots whose brains are not impressioned with the entire First Law of Robotics.”
   “Aren’t impressioned?” Calvin slumped back in her chair, “I see. How many were made?”
   “A few. It was on government order and there was no way of violating the secrecy. No one was to know except the top men directly concerned. You weren’t included, Susan. It was nothing I had anything to do with.”
   The general interrupted with a measure of authority. “I would like to explain that bit. I hadn’t been aware that Dr. Calvin was unacquainted with the situation. I needn’t tell you, Dr. Calvin, that there always has been strong opposition to robots on the Planet. The only defense the government has had against the Fundamentalist radicals in this matter was the fact that robots are always built with an unbreakable First Law—which makes it impossible for them to harm human beings under any circumstance.
   “But we had to have robots of a different nature. So just a few of the NS-2 model, the Nestors, that is, were prepared with a modified First Law. To keep it quiet, all NS-2’s are manufactured without serial numbers; modified members are delivered here along with a group of normal robots; and, of course, all our kind are under the strictest impressionment never to tell of their modification to unauthorized personnel.” He wore an embarrassed smile; “This has all worked out against us now.”
   Calvin said grimly, “Have you asked each one who it is, anyhow? Certainly, you are authorized?”
   The general nodded, “All sixty-three deny having worked here—and one is lying.”
   “Does the one you want show traces of wear? The others, I take it, are factory-fresh.”
   “The one in question only arrived last month. It, and the two that have just arrived, were to be the last we needed. There’s no perceptible wear.” He shook his head slowly and his eyes were haunted again, “Dr. Calvin, we don’t dare let that ship leave. If the existence of non-First Law robots becomes general knowledge—” There seemed no way of avoiding understatement in the conclusion.
   “Destroy all sixty-three,” said the robopsychologist coldly and flatly, “and make an end of it.”
   Bogert drew back a corner of his mouth. “You mean destroy thirty thousand dollars per robot. I’m afraid U. S. Robots wouldn’t like that. We’d better make an effort first, Susan, before we destroy anything.”
   “In that case,” she said, sharply, “I need facts. Exactly what advantage does Hyper Base derive from these modified robots? What factor made them desirable, general?”
   Kallner ruffled his forehead and stroked it with an upward gesture of his hand. “We had trouble with our previous robots. Our men work with hard radiations a good deal, you see. It’s dangerous, of course, but reasonable precautions are taken. There have been only two accidents since we began and neither was fatal. However, it was impossible to explain that to an ordinary robot. The First Law states—I’ll quote it—‘No robot may harm a human being, or through inaction, allow a human being to come to harm.’
   “That’s primary, Dr. Calvin. When it was necessary for one of our men to expose himself for a short period to a moderate gamma field, one that would have no physiological effects, the nearest robot would dash in to drag him out. If the field were exceedingly weak, it would succeed, and work could not continue till all robots were cleared out. If the field were a trifle stronger, the robot would never reach the technician concerned, since its positronic brain would collapse under gamma radiations—and then we would be out one expensive and hard-to-replace robot.
   “We tried arguing with them. Their point was that a human being in a gamma field was endangering his life and that it didn’t matter that he could remain there half an hour safely. Supposing, they would say, he forgot and remained an hour. They couldn’t take chances. We pointed out that they were risking their lives on a wild off-chance. But self-preservation is only the Third Law of Robotics—and the First Law of human safety came first. We gave them orders; we ordered them strictly and harshly to remain out of gamma fields at whatever cost. But obedience is only the Second Law of Robotics—and the First Law of human safety came first. Dr. Calvin, we either had to do without robots, or do something about the First Law—and we made our choice.”
   “I can’t believe,” said Dr. Calvin, “that it was found possible to remove the First Law.”
   “It wasn’t removed, it was modified,” explained Kallner. “Positronic brains were constructed that contained the positive aspect only of the Law, which in them reads: ‘No robot may harm a human being.’ That is all. They have no compulsion to prevent one coming to harm through an extraneous agency such as gamma rays. I state the matter correctly, Dr. Bogert?”
   “Quite,” assented the mathematician.