Stubbornly Elijah Baley fought panic.

For two weeks it had been building up. Longer than that, even. It had been building up ever since they had called him to Washington and there calmly told him he was being reassigned.

The call to Washington had been disturbing enough in itself. It came without details, a mere summons; and that made it worse. It included travel slips directing round trip by plane and that made it still worse.

Partly it was the sense of urgency introduced by any order for plane travel. Partly it was the thought of the plane; simply that. Still, that was just the beginning of uneasiness and, as yet, easy to suppress.

After all, Lije Baley had been in a plane four times before. Once he had even crossed the continent. So, while plane travel is never pleasant, it would, at least, not be a complete step into the unknown.

And then, the trip from New York to Washington would take only an hour. The take-off would be from New York Runway Number 2, which, like all official Runways, was decently enclosed, with a lock opening to the unprotected atmosphere only after air speed had been achieved. The arrival would be at Washington Runway Number 5, which was similarly protected.

Furthermore, as Baley well knew, there would be no windows on the plane. There would be good lighting, decent food, all necessary conveniences. The radio-controlled flight would be smooth; there would scarcely be any sensation of motion once the plane was airborne.

He explained all this to himself, and to Jessie, his wife, who had never been air-borne and who approached such matters with terror.

She said, "But I don't like you to take a plane, Lije. It isn't natural. Why can't you take the Expressways?"

"Because that would take ten hours" - Baley's long face was set in dour lines - "and because I'm a member of the City Police Force and have to follow the orders of my superiors. At least, I do if I want to keep my C-6 rating."

There was no arguing with that.

Baley took the plane and kept his eyes firmly on the news-strip that unreeled smoothly and continuously from the eye-level dispenser. The City was proud of that service: news, features, humorous articles, educational bits, occasional fiction. Someday the strips would be converted to film, it was said, since enclosing the eyes with a viewer would be an even more efficient way of distracting the passenger from his surroundings.

Baley kept his eyes on the unreeling strip, not only for the sake of distraction, but also because etiquette required it. There were five other passengers on the plane (he could not help noticing that much) and each one of them had his private right to whatever degree of fear and anxiety his nature and upbringing made him feel.

Baley would certainly resent the intrusion of anyone else on his own uneasiness. He wanted no strange eyes on the whiteness of his knuckles where his hands gripped the armrest, or the dampish stain they would leave when he took them away.

He told himself: I'm enclosed. This plane is just a little City. But he didn't fool himself. There was an inch of steel at his left; he could feel it with his elbow. Past that, nothing - Well, air! But that was nothing, really.

A thousand miles of it in one direction. A thousand in another. One mile of it, maybe two, straight down.

He almost wished he could see straight down, glimpse the top of the buried Cities he was passing over; New York, Philadelphia, Baltimore, Washington. He imagined the rolling, low-slung cluster complexes of domes he had never seen but knew to be there. And under them, for a mile underground and dozens of miles in every direction, would be the Cities.

The endless, hiving corridors of the Cities, he thought, alive with people; apartments, community kitchens, factories, Expressways; all comfortable and warm with the evidence of man.

And he himself was isolated in the cold and Featureless air in a small bullet of metal, moving through emptiness.

His hands trembled, and he forced his eyes to focus on the strip of paper and read a bit.

It was a short story dealing with Galactic exploration and it was quite obvious that the hero was an Earthman.

Baley muttered in exasperation, then held his breath momentarily in dismay at his boorishness in making a sound.

It was completely ridiculous, though. It was pandering to childishness, this pretense that Earthmen could invade space. Galactic exploration! The Galaxy was closed to Earthmen. It was pre-empted by the Spacers, whose ancestors had been Earthmen centuries before. Those ancestors had reached the Outer Worlds first, found themselves comfortable, and their descendants had lowered the bars to immigration. They had penned in Earth and their Earthman cousins. And Earth's City civilization completed the task, imprisoning Earthmen within the Cities by a wall of fear of open spaces that barred them from the robot-run farming and mining areas of their own planet; from even that.

Baley thought bitterly: Jehoshaphat! If we don't like it, let's do something about it. Let's not just waste time with fairy tales.

But there was nothing to do about it, and he knew it.

Then the plane landed. He and his fellow-passengers emerged and scattered away from one another, never looking.

Baley glanced at his watch and decided there was time for freshening before taking the Expressway to the Justice Department. He was glad there was. The sound and clamor of life, the huge vaulted chamber of the airport with City corridors leading off on numerous levels, everything else he saw and heard, gave him the feeling of being safely and warmly enclosed in the bowels and womb of the City. It washed away anxiety and only a shower was necessary to complete the job.

He needed a transient's permit to make use of one of the community bathrooms, but presentation of his travel orders eliminated any difficulties. There was only the routine stamping, with private stall privileges (the date carefully marked to prevent abuse) and a slim strip of directions for getting to the assigned spot.

Baley was thankful for the feel of the strips beneath his feet. It was with something amounting to luxury that he felt himself accelerate as he moved from strip to moving strip inward toward the speeding Expressway. He swung himself aboard lightly, taking the seat to which his rating entitled him.

It wasn't a rush hour; seats were available. The bathroom, when he reached it, was not unduly crowded either. The stall assigned to him was in decent order with a launderette that worked well.

With his water ration consumed to good purpose and his clothing freshened he felt ready to tackle the Justice Department. Ironically enough, he even felt cheerful.

Undersecretary Albert Minnim was a small, compact man, ruddy of skin, and graying, with the angles of his body smoothed down and softened. He exuded an air of cleanliness and smelled faintly of tonic. It all spoke of the good things of life that came with the liberal rations obtained by those high in Administration.

Baley felt sallow and rawboned in comparison. He was conscious of his own large hands, deep-set eyes, a general sense of cragginess.

Minnim said cordially, "Sit down, Baley. Do you smoke?"

"Only a pipe, sir," said Baley.

He drew it out as he spoke, and Minnim thrust back a cigar he had half drawn.

Baley was instantly regretful. A cigar was better than nothing and he would have appreciated the gift. Even with the increased tobacco ration that went along with his recent promotion from C-5 to C-6 he wasn't exactly swimming in pipe fixings.

"Please light up, if you care to," said Minnim, and waited with a kind of paternal patience while Baley measured out a careful quantity of tobacco and affixed the pipe baffle.

Baley said, his eyes on his pipe, "I have not been told the reason for my being called to Washington, sir."

"I know that," said Minnim. He smiled "I can fix that right now. You are being reassigned temporarily."

"Outside New York City?"

"Quite a distance."

Baley raised his eyebrows and looked thoughtful. "How temporarily, sir?"

"I'm not sure."

Baley was aware of the advantages and disadvantages of reassignment. As a transient in a City of which he was not a resident, be would probably live on a scale better than his official rating entitled him to. On the other hand, it would be very unlikely that Jessie and their son, Bentley, would be allowed to travel with him. They would be taken care of, to be sure, there in New York, but Baley was a domesticated creature and he did not enjoy the thought of separation.

Then, too, a reassignment meant a specific job of work, which was good, and a responsibility greater than that ordinarily expected of the individual detective, which could be uncomfortable. Baley had, not too many months earlier, survived the responsibility of the investigation of the murder of a Spacer just outside New York. He was not overjoyed at the prospect of another such detail, or anything approaching it.

He said, "Would you tell me where I'm going? The nature of the reassignment? What it's all about?"

He was trying to weigh the Undersecretary's "Quite a distance" and make little bets with himself as to his new base of operations. The "Quite a distance" had sounded emphatic and Baley thought:

Calcutta? Sydney?

Then he noticed that Minnim was taking out a cigar after all and was lighting it carefully.

Baley thought: Jehoshaphat! He's having trouble telling me. He doesn't want to say.

Minnim withdrew his cigar from between his lips. He watched the smoke and said, "The Department of Justice is assigning you to temporary duty on Solaria."

For a moment Baley's mind groped for an illusive identification:

Solaria, Asia; Solaria, Australia...

Then he rose from his seat and said tightly, "You mean, one of the Outer Worlds?"

Minnim didn't meet Baley's eyes. "That is right!"

Baley said, "But that's impossible. They wouldn't allow an Earthman on an Outer World."

"Circumstances do alter cases, Plainclothesman Baley. There has been a murder on Solaria."

Baley's lips quirked into a sort of reflex smile. "That's a little out of our jurisdiction, isn't it?"

"They've requested help."

"From us? From Earth?" Baley was torn between confusion and disbelief. For an Outer World to take any attitude other than contempt toward the despised mother planet or, at best, a patronizing social benevolence was unthinkable. To come for help?

"From Earth?" he repeated.

"Unusual," admitted Minnim, "but there it is. They want a Terrestrial detective assigned to the case. It's been handled through diplomatic channels on the highest levels."

Baley sat down again. "Why me? I'm not a young man. I'm forty three. I've got a wife and child. I couldn't leave Earth."

"That's not our choice, Plainclothesman. You were specifically asked for."

"Plainclothesman Elijah Baley, C-6, of the New York City Police Force. They knew what they wanted. Surely you see why."

Baley said stubbornly, "I'm not qualified."

"They think you are. The way you handled the Spacer murder has apparently reached them."

"They must have got it all mixed up. It must have seemed better than it was."

Minnim shrugged. "In any case, they've asked for you and we have agreed to send you. You are reassigned. The papers have all been taken care of and you must go. During your absence, your wife and child will be taken care of at a C-7 level since that will be your temporary rating during your discharge of this assignment." He paused significantly. "Satisfactory completion of the assignment may make the rating permanent."

It was happening too quickly for Baley. None of this could be so. He couldn't leave Earth. Didn't they see that?

He heard himself ask in a level voice that sounded unnatural in his own ears. "What kind of a murder? What are the circumstances? Why can't they handle it themselves?"

Minnim rearranged small objects on his desk with carefully kept fingers. He shook his head. "I don't know anything about the murder. I don't know the circumstances."

"Then who does, sir? You don't expect me to go there cold, do you?" And again a despairing inner voice: But I can't leave Earth.

"Nobody knows anything about it. Nobody on Earth. The Solarians didn't tell us. That will be your job; to find out what is so important about the murder that they must have an Earthman to solve it. Or, rather, that will be part of your job."

Baley was desperate enough to say, "What if I refuse?" He knew the answer, of course. He knew exactly what declassification would mean to himself and, more than that, to his family.

Minnim said nothing about declassification. He said softly, "You can't refuse, Plainclothesman. You have a job to do."

"For Solaria? The hell with them."

"For us, Baley. For us." Minnim paused. Then he went on, "You know the position of Earth with respect to the Spacers. I don't have to go into that."

Baley knew the situation and so did every man on Earth. The fifty Outer Worlds, with a far smaller population, in combination, than that of Earth alone, nevertheless maintained a military potential perhaps a hundred times greater. With their underpopulated worlds resting on a positronic robot economy, their energy production per human was thousands of times that of Earth. And it was the amount of energy a single human could produce that dictated military potential, standard of living, happiness, and all besides.

Minnim said, "One of the factors that conspires to keep us in that position is ignorance. Just that. Ignorance. The Spacers know all about us. They send missions enough to Earth, heaven knows. We know nothing about them except what they tell us. No man on Earth has ever as much as set foot on an Outer World. You will, though."

Baley began, "I can't - "

But Minnim repeated, "You will. Your position will be unique. You will be on Solaria on their invitation, doing a job to which they will assign you. When you return, you will have information useful to Earth."

Baley watched the Undersecretary through somber eyes. "You mean I'm to spy for Earth."

"No question of spying. You need do nothing they don't ask you to do. Just keep your eyes and mind open. Observe! There will be specialists on Earth when you return to analyze and interpret your observations."

Baley said, "I take it there's a crisis, sir."

"Why do you say that?"

"Sending an Earthman to an Outer World is risky. The Spacers hate us. With the best will in the world and even though I'm there on invitation, I could cause an interstellar incident. The Terrestrial Government could easily avoid sending me if they chose. They could say I was ill. The Spacers are pathologically afraid of disease. They wouldn't want me for any reason if they thought I were ill."

"Do you suggest," said Minnim, "we try that trick?"

"No. If the government had no other motive for sending me, they would think of that or something better without my help. So it follows that it is the question of spying that is the real essential. And if that is so, there must be more to it than just a see-what-you-can see to justify the risk."

Baley half expected an explosion and would have half welcomed one as a relief of pressure, but Minnim only smiled frostily and said, "You can see past the non-essentials, it seems. But then, I expected no less."

The Undersecretary leaned across his desk toward Baley. "Here is certain information which you will discuss with no one, not even with other government officials. Our sociologists have been coming to certain conclusions concerning the present Galactic situation. Fifty Outer Worlds, underpopulated, roboticized, powerful, with people that are healthy and long-lived. We ourselves, crowded, technologically underdeveloped, short-lived, under their domination. It is unstable."

"Everything is in the long run."

"This is unstable in the short run. A hundred years is the most we're allowed. The situation will last our time, to be sure, but we have children. Eventually we will become too great a danger to the Outer Worlds to be allowed to survive. There are eight billions on Earth who hate the Spacers."

Baley said, "The Spacers exclude us from the Galaxy, handle our trade to their own profit, dictate to our government, and treat us with contempt. What do they expect? Gratitude?"

"True, and yet the pattern is fixed. Revolt, suppression, revolt, suppression - and within a century Earth will be virtually wiped out as a populated world. So the sociologists say."

Baley stirred uneasily. One didn't question sociologists and their computers. "But what do you expect me to accomplish if all this is so?"

"Bring us information. The big flaw in sociological forecast is our lack of data concerning the Spacers. We've had to make assumptions on the basis of the few Spacers they sent out here. We've had to rely on what they choose to tell us of themselves, so it follows we know their strengths and only their strengths. Damn it, they have their robots and their low numbers and their long lives. But do they have weaknesses? Is there some factor or factors which, if we but knew, would alter the sociologic inevitability of destruction; something that could guide our actions and better the chance of Earth's survival."

"Hadn't you better send a sociologist, sir?"

Minnim shook his head. "If we could send whom we pleased, we would have sent someone out ten years ago, when these conclusions were first being arrived at. This is our first excuse to send someone and they ask for a detective and that suits us. A detective is a sociologist, too; a rule-of-thumb, practicing sociologist, or he wouldn't be a good detective. Your record proves you a good one."

"Thank you, sir," said Baley mechanically. "And if I get into trouble?"

Minriim shrugged. "That's the risk of a policeman's job." He dismissed the point with a wave of his hand and added, "In any case, you must go. Your rime of departure is set. The ship that will take you is waiting."

Baley stiffened. "Waiting? When do I leave?"

"In two days."

"I've got to get back to New York then. My wife - "

"We will see your wife. She can't know the nature of your job, you know. She will be told not to expect to hear from you."

"But this is inhuman. I must see her. I may never see her again." Minnim said, "What I say now may sound even more inhuman, but isn't it true that there is never a day you set about your duties on which you cannot tell yourself she may never see you again? Plainclothesman Baley, we must all do our duty."

Baley's pipe had been out for fifteen minutes. He had never noticed it.

No one had more to tell him. No one knew anything about the murder. Official after official simply hurried him on to the moment when he stood at the base of a spaceship, all unbelieving still.

It was like a gigantic cannon aimed at the heavens, and Baley shivered spasmodically in the raw, open air. The night closed in (for which Baley was thankful) like dark black walls melting into a black ceiling overhead. It was cloudy, and though he had been to Planetaria, a bright star, stabbing through a rift in the cloud, startled him when it caught his eyes.

A little spark, far, far away. He stared curiously, almost unafraid of it. It looked quite close, quite insignificant, and yet around things like that circled planets of which the inhabitants were lords of the Galaxy. The sun was a thing like that, he thought, except much closer, shining now on the other side of the Earth.

He thought of the Earth suddenly as a ball of stone with a film of moisture and gas, exposed to emptiness on every side, with its Cities barely dug into the outer rim, clinging precariously between rock and air. His skin crawled!

The ship was a Spacer vessel, of course. Interstellar trade was entirely in Spacer hands. He was alone now, just outside the rim of the City. He had been bathed and scraped and sterilized until he was considered safe, by Spacer standards, to board the ship. Even so, they sent only a robot out to meet him, bearing as he did a hundred varieties of disease germs from the sweltering City to which he himself was resistant but to which the eugenically hot housed Spacers were not.

The robot bulked dimly in the night, its eyes a dull red glow.

"Plainclothesman Elijah Baley?"

"That's right," said Baley crisply, the hair on the nape of his neck stirring a bit. He was enough of an Earthman to get angry goose flesh at the sight of a robot doing a man's job. There had been R. Daneel Olivaw, who had partnered with him in the Spacer murder affair, but that had been different. Daneel had been - "You will follow me, please," said the robot, and a white light flooded a path toward the ship.

Baley followed. Up the ladder and into the ship he went, along corridors, and into a room.

The robot said, "This will be your room, Plainclothesman Baley. It is requested that you remain in it for the duration of the trip."

Baley thought: Sure, seal me off. Keep me safe. Insulated.

The corridors along which he had traveled had been empty. Robots were probably disinfecting them now. The robot facing him would probably step through a germicidal bath when it left.

The robot said, "There is a water supply and plumbing. Food will be supplied. You will have viewing matter. The ports are controlled from this panel. They are closed now but if you wish to view space - "

Baley said with some agitation, "That's all right, boy. Leave the ports closed."

He used the "boy" address that Earthmen always used for robots, but the robot showed no adverse response. It couldn't, of course. Its responses were limited and controlled by the Laws of Robotics.

The robot bent its large metal body in the travesty of a respectful bow and left.

Baley was alone in his room and could take stock. It was better than the plane, at least. He could see the plane from end to end. He could see its limits. The spaceship was large. It had corridors, levels, rooms. It was a small City in itself. Baley could almost breathe freely.

Then lights flashed and a robot's metallic voice sounded over the communo and gave him specific instructions for guarding himself against take-off acceleration.

There was the push backward against webbing and a yielding hydraulic system, a distant rumble of force-jets heated to fury by the proton micro-pile. There was the hiss of tearing atmosphere, growing thinner and high-pitched and fading into nothingness after an hour.

They were in space.

It was as though all sensation had numbed, as though nothing were real. He told himself that each second found him thousands of miles farther from the Cities, from Jessie, but it didn't register.

On the second day (the third? - there was no way of telling time except by the intervals of eating and sleeping) there was a queer momentary sensation of being turned inside out. It lasted an instant and Baley knew it was a Jump, that oddly incomprehensible, almost mystical, momentary transition through hyperspace that transferred a ship and all it contained from one point in space to another, light years away. Another lapse of time and another Jump, still another lapse, still another Jump.

Baley told himself now that he was light-years away, tens of light years, hundreds, thousands.

He didn't know how many. No one on Earth as much as knew Solaria's location in space. He would bet on that. They were ignorant, every one of them.

He felt terribly alone.

There was the feel of deceleration and the robot entered. Its somber, ruddy eyes took in the details of Baley's harness. Efficiently it tightened a wing nut; quickly it surveyed the details of the hydraulic system.

It said, "We will be landing in three hours. You will remain, if you please, in this room. A man will come to escort you out and to take you to your place of residence."

"Wait," said Baley tensely. Strapped in as he was, he felt helpless. "When we land, what time of day will it be?"

The robot said at once, "By Galactic Standard Time, it will be - "

"Local time, boy. Local time! Jehoshaphat!"

The robot continued smoothly, "The day on Solaria is twenty eight point thirty-five Standard hours in length. The Solarian hour is divided into ten decades, each of which is divided into a hundred centads. We are scheduled to arrive at an airport at which the day will be at the twentieth centad of the fifth decad."

Baley hated that robot. He hated it for its obtuseness in not understanding; for the way it was making him ask the question directly and exposing his own weakness.

He had to. He said flatly, "Will it be daytime?"

And after all that the robot answered, "Yes, sir," and left.

It would be day! He would have to step out onto the unprotected surface of a planet in daytime.

He was not quite sure how it would be. He had seen glimpses of planetary surfaces from certain points within the City; he had even been out upon it for moments. Always, though, he had been surrounded by walls or within reach of one. There was always safety at hand.

Where would there be safety now? Not even the false walls of darkness.

And because he would not display weakness before the Spacers - he'd be damned if he would - he stiffened his body against the webbing that held him safe against the forces of deceleration, closed his eyes, and stubbornly fought panic.