"I've just heard from the police. He's got quite a procession with him, and it's snarled up the traffic. He should be here any moment now."

He heard the door open behind him, but did not turn his head as Pieter Van Ryberg came into the room. There was the inevitable pause as Pieter looked disapprovingly at the thermostat, for it was a standing joke that the Secretary-General liked living in an icebox. Stormgren waited until his assistant joined him at the window, then tore his gaze away from the familiar yet always fascinating panorama below.

The Secretary-General of the United Nations stood motionless by the great window, staring down at the crawling traffic on 43rd Street. He sometimes wondered if it was a good thing for any man to work at such an altitude above his fellow humans. Detachment was all very well, but it could change so easily to indifference. Or was he merely trying to rationalize his dislike of skyscrapers, still unabated after twenty years in New York?

"They're late," he said. "Wainwright should have been here five minutes ago."

Van Ryberg paused, then added abruptly, "Are you still sure it's a good idea to see him?"

Stormgren picked up his notebook and rejoined his assistant. Half a mile away, a small but determined crowd was moving slowly towards the Secretariat Building. It carried banners that were indecipherable at this distance, but Stormgren knew their message well enough. Presently he could hear, rising above the sound of the traffic, the ominous rhythm of chanting voices. He felt a sudden wave of disgust sweep over him. Surely the world had had enough of marching mobs and angry slogans!

"I'm afraid it's a little late to back out of it now. After all, I've agreed -- though as you know it was never my idea in the first place."

Stormgren had walked to his desk and was fidgeting with his famous uranium paperweight. He was not nervous-merely undecided. He was also glad that Wainwright was late, for that would give him a slight moral advantage when the interview opened. Such trivialities played a greater part in human affairs than anyone who set much store on logic and reason might wish.

"Here they are!" said Van Ryberg suddenly, pressing his face against the window. "They're coming along the Avenue -- a good three thousand, I'd say."

And very probably, thought Stormgren, Karellen was watching the whole thing and enjoying himself hugely, for this meeting would never have taken place except at the Supervisor's instigation.

Alexander Wainwright was a tall, handsome man in the late forties. He was, Stormgren knew, completely honest, and therefore doubly dangerous. Yet his obvious sincerity made it hard to dislike him, whatever views one might have about the cause for which he stood -- and some of the followers he had attracted.

The crowd had now come abreast of the building; it must know that he was watching, for here and there fists were being shaken, rather self-consciously, in the air. They were not defying him, though the gesture was doubtless meant for Stormgren to see. As pygmies may threaten a giant, so those angry fists were directed against the sky fifty kilometres above his head-against the gleaming silver cloud that was the flagship of the Overlord fleet.

This was the first time that Stormgren had ever met the head of the Freedom League. He had ceased to wonder if the action was wise, for Karellen's plans were often too subtle for merely human understanding. At the worst, Stormgren did not see that any positive harm could be done. If he had refused to see Wainwright, the League would have used the fact as ammunition against him.

Stormgren wasted no time after Van Ryberg's brief and somewhat strained introductions.

"I suppose," he began, "the chief object of your visit is to register a formal protest against the Federation Scheme. Am I correct?"

Wainwright nodded gravely.

"That is my main protest, Mr. Secretary. As you know, for the last five years we have tried to awaken the human race to the danger that confronts it. The task has been a difficult one, for the majority of people seem content to let the Overlords run the world as they please. Nevertheless, more than five million patriots, in every country, have signed our petition."

"What does anyone know of Karellen's powers?" retorted Stormgren. "When I was a boy, the Federation of Europe was a dream -- but when I grew to manhood it had become reality. And that was before the arrival of the Overlords. Karellen is merely finishing the work we had begun."

"That is not a very impressive figure out of two and a half billion."

"It is a figure that cannot be ignored. And for every person who has signed, there are many who feel grave doubts about the wisdom, not to mention the rightness of this Federation plan. Even Supervisor Karellen, for all his powers, cannot wipe out a thousand years of history at the stroke of a pen."

"Europe was a cultural and geographical entity. The world is not -- that is the difference."

"To the Overlords," replied Stormgren sarcastically, "the Earth is probably a great deal smaller than Europe seemed to our fathers -- and their outlook, I submit, is more mature than ours."

"Let me ask you a few questions," he said. "Can you deny that the Overlords have brought security, peace and prosperity to the world?"

"I do not necessarily quarrel with Federation as an ultimate objective -- though many of my supporters might not agree. But it must come from within -- not be superimposed from without. We must work out our own destiny. There must be no more interference in human affairs!"

Stormgren sighed. All this he had heard a hundred times before, and he knew that he could only give the old answer that the Freedom League had refused to accept. He had faith in Karellen, and they had not. That was the fundamental difference, and there was nothing he could do about it. Luckily, there was nothing that the Freedom League could do, either.

"-- by bread alone. Yes, I know -- but this is the first age in which every man was sure of getting even that. In any case, what freedom have we lost compared with that which the Overlords have given us for the first time in human history?"

"That is true. But they have taken our liberty. Man does not live --"

At last, thought Stormgren, we've got to the point. Basically, the conflict is a religious one, however much it may be disguised. Wainwright never let you forget he was a clergyman. Though he no longer wore a clerical collar, somehow one always got the impression it was still there.

Wainwright shook his head in angry denial.

"Last month," pointed out Stormgren, "a hundred bishops, cardinals and rabbis signed a joint declaration pledging their support for the Supervisor's policy. The world's religions are against you."

"Freedom to control our own lives, under God's guidance."

"Many of the leaders are blind; they have been corrupted by the Overlords. When they realize the danger, it may be too late. Humanity will have lost its initiative and become a subject race."

"In three days I will be meeting the Supervisor again. I will explain your objections to him, since it is my duty to represent the views of the world. But it will alter nothing -- I can assure you of that."

There was silence for a moment. Then Stormgren replied;

Stormgren was silent. There was nothing he could say to this -- nothing, at any rate, that would convince the other. He sometimes wondered if he had really convinced himself.

"Despite all that he has done for humanity?"

"There is one other point," said Wainwright slowly. "We have many objections to the Overlords -- but above all we detest their secretiveness. You are the only human being who has ever spoken with Karellen, and even you have never seen him! Is it surprising that we doubt his motives?"

"Yes -- despite that. I do not know which we resent more -- Karellen's omnipotence, or his secrecy. If he has nothing to hide, why will he never reveal himself? Next time you speak with the Supervisor, Mr. Stormgren, ask him that!"

It was, of course, only a very small operation from their point of view, but to Earth it was the biggest thing that had ever happened. There had been no warning when the great ships came pouring out of the unknown depths of space.

Even before the ending of those heart-freezing days, some men had guessed the truth. This was not the first tentative contact by a race which knew nothing of man. Within those silent, unmoving ships, master psychologists were studying humanity's reactions. When the curve of tension had reached its peak, they would act.

And on the sixth day, Karellen, Supervisor for Earth, made himself known to the world in a broadcast that blanketed every radio frequency. He spoke in English so perfect that the controversy it began was to rage across the Atlantic for a generation. But the context of the speech was more staggering even than its delivery. By any standards, it was a work of superlative genius, showing a complete and absolute mastery of human affairs. There could be no doubt that its scholarship and virtuosity, its tantalizing glimpses of knowledge still untapped were deliberately designed to convince mankind that it was in the presence of overwhelming intellectual power. When Karellen had finished, the nations of Earth knew that their days of precarious sovereignty had ended. Local, internal governments would still retain their powers, but in the wider field of international affairs the supreme decisions had passed from human hands. Arguments-protests-all were futile.

Countless times this day had been described in fiction, but no-one had really believed that it would ever come. Now it had dawned at last; the gleaming, silent shapes hanging over every land were the symbol of a science Man could not hope to match for centuries. For six days they floated motionless above his cities, giving no hint they knew of his existence. But none was needed; not by chance alone could those mighty ships have come to rest so precisely over New York, London, Paris, Moscow, Rome, Cape Town, Tokyo, Canberra…

It was hardly to be expected that all the nations of the world would submit tamely to such a limitation of their powers. Yet active resistance presented baffling difficulties, for the destruction of the Overlords' ships, even if it could be achieved, would annihilate the cities beneath them.

The screen became suddenly blank as the missile destroyed itself on impact, and the picture switched immediately to an airborne camera many miles away. In the fraction of a second that had elapsed, the fireball should already have formed and should be filling the sky with its solar flame.

As the great ship's image had expanded on the television screen in the secret control room, the little group of officers and technicians must have been torn by many emotions. If they succeeded -- what action would the remaining ships take? Could they also be destroyed, leaving humanity to go its own way once more? Or would Karellen wreak some frightful vengeance upon those who had attacked him?

Nevertheless, one major power had made the attempt. Perhaps those responsible hoped to kill two birds with one atomic missile, for their target was floating above the capital of an adjoining and unfriendly nation.

Yet nothing whatsoever had happened. The great ship floated unharmed, bathed in the raw sunlight at the edge of space. Not only had the bomb failed to touch it, but no one could ever decide what had happened to the missile. Moreover, Karellen took no action against those responsible, or even indicated that he had known of the attack. He ignored them contemptuously, leaving them to worry over a vengeance that never came. It was a more effective, and more demoralizing, treatment than any punitive action could have been. The government responsible collapsed completely in mutual recrimination a few weeks later.

There had also been some passive resistance to the policy of the Overlords. Usually, Karellen had been able to deal with it by letting those concerned have their own way, until they had discovered that they were only hurting themselves by their refusal to cooperate. Only once had he taken any direct action against a recalcitrant government.

For more than a hundred years, the Republic of South Africa had been the centre of social strife. Men of good will on both sides had tried to build a bridge, but in vain-fears and prejudices were too deeply ingrained to permit any cooperation. Successive governments had differed only by the degree of their intolerance; the land was poisoned with hate and the aftermath of civil war.

Nor did they. All that happened was that as the sun passed the meridian at Cape Town -- it went out. There remained visible merely a pale, purple ghost, giving no heat or light. Somehow, out in space, the light of the sun had been polarized by two crossed fields so that no radiation could pass. The area affected was five hundred kilometres across, and perfectly circular.

The demonstration lasted thirty minutes. It was sufficient; the next day the Government of South Africa announced that full civil rights would be restored to the white minority.

When it became clear that no attempt would be made to end discrimination, Karellen gave his warning. It merely named a date and time -- no more. There was apprehension, but little fear or panic, for no-one believed that the Overlords would take any violent or destructive action which would involve innocent and guilty alike.

Apart from such isolated incidents, the human race had accepted the Overlords as part of the natural order of things. In a surprisingly short time, the initial shock had worn off, and the world went about its business again. The greatest change a suddenly awakened Rip Van Winkle would have noticed was a hushed expectancy, a mental glancing-over-the-shoulder, as mankind waited for the Overlords to show themselves and to step down from their gleaming ships.

There was the usual circle of sightseers, cameras at the ready, as Stormgren's car drove on to the launching-field. The Secretary-General exchanged a few final words with his assistant, collected his brief case, and walked through the ring of spectators.

Five years later, it was still waiting. That, thought Stormgren, was the cause of all the trouble.

Karellen never kept him waiting for long. There was a sudden "Oh!" from the crowd, and a silver bubble expanded with breathtaking speed in the sky above. A gust of air tore at Stormgren's clothes as the tiny ship came to rest fifty metres away, floating delicately a few centimetres above the ground, as if it feared contamination with Earth. As he walked slowly forward, Stormgren saw that familiar puckering of the seamless metallic hull, and in a moment the opening that had so baffled the world's best scientists appeared before him. He stepped through it into the ship's single, softly-lit room. The entrance sealed itself as if it had never been, shutting out all sound and sight.

It opened again five minutes later. There had been no sensation of movement, but Stormgren knew that he was now fifty kilometres above the Earth, deep in the heart of Karellen's ship. He was in the world of the Overlords; all around him, they were going about their mysterious business. He had come nearer to them than had any other man; yet he knew no more of their physical nature than did any of the millions on the world below.

Sometimes in his dreams Stormgren had imagined that it had suddenly flashed into life, revealing the secret that tormented all the world. But the dream had never come true; behind that rectangle of darkness lay utter mystery. Yet there also lay power and wisdom -- and, perhaps most of all, an immense and humorous affection for the little creatures crawling on the planet beneath.

The little conference room at the end of the short connecting corridor was unfurnished apart from the single chair and the table beneath the vision screen. As was intended, it told absolutely nothing of the creatures who had built it. The vision screen was empty now, as it had always been.

"Yes, Rikki, I was listening to your little interview. What did you make of Mr. Wainwright?"

"He's an honest man, even if many of his supporters aren't. What are we going to do about him? The League itself isn't dangerous -- but some of its extremists are openly advocating violence. I've been wondering if I should put a guard on my house. But I hope it isn't necessary."

From the hidden grille came that calm, never-hurried voice that Stormgren knew so well though the world had heard it only once in history. Its depth and resonance gave the single clue that existed in Karellen's physical nature, for it left an overwhelming impression of sheer size. Karellen was large -- perhaps much larger than a man. It was true that some scientists, after analyzing the record of his only speech, had suggested that the voice was that of a machine. This was something that Stormgren could never believe.

Karellen evaded the point in the annoying way he sometimes had.

"The details of the World Federation have been out for a month now. Has there been a substantial increase in the seven percent who don't approve of me, or the twelve percent who don't know?"

"Not yet. But that's of no importance; what does worry me is a general feeling, even among your supporters, that it's time this secrecy came to an end."

Karellen's sigh was technically perfect, yet somehow lacked conviction.

"I wonder if you really appreciate," he continued earnestly, "how difficult this state of affairs makes my job?"

"That's your feeling too, isn't it?"

The question was so rhetorical that Stormgren did not bother to answer it.

"Can't you at least give us some reason for your concealment? Because we don't understand it, it annoys us and gives rise to endless rumours."

"What am I supposed to be now? Does the robot theory still hold the field? I'd rather be a mass of electron tubes than a thing like a centipede -- oh yes, I've seen that cartoon in yesterday's Chicago Tribune! I'm thinking of requesting the original."

"It doesn't exactly help mine," replied Karellen with some spirit. "I wish people would stop thinking of me as a dictator, and remember I'm only a civil servant trying to administer a colonial policy in whose shaping I had no hand."

That, thought Stormgren, was quite an engaging description. He wondered just how much truth it held.

Karellen gave that rich, deep laugh of his, just too resonant, to be altogether human.

"This is serious," he said reprovingly. "My dear Rikki," Karellen retorted, "it's only by not taking the human race seriously that I retain what fragments of my once considerable mental powers I still possess!"

Stormgren pursed his lips primly. There were times, he thought, when Karellen took his duties too lightly.

Despite himself Stormgren smiled.

"Of all the problems that faced us when we came to Earth, this was the most difficult," admitted Karellen. "You have trusted our wisdom in other matters -- surely you can trust us in this!"

"That doesn't help me a great deal, does it? I have to go down there and convince my fellow men that although you won't show yourself, you've got nothing to hide. It's not an easy job. Curiosity is one of the most dominant of human characteristics. You can't defy it forever."

"I trust you," said Stormgren, "but Wainwright doesn't, nor do his supporters. Can you really blame them if they put a bad interpretation on your unwillingness to show yourselves?"

There was silence for a moment. Then Stormgren heard that faint sound (was it a crackling?) that might have been caused by the Supervisor moving his body slightly.

"And do you?" whispered Stormgren, half to himself.

"That, Rikki, is the fear that torments them, even though they will never admit it openly. Believe me, it gives us no pleasure to destroy men's faiths, but all the world's religions cannot be right, and they know it. Sooner or later man has to learn the truth; but that time is not yet. As for our secrecy, which you are correct in saying aggravates our problems -- that is a matter beyond my control. I regret the need for this concealment as much as you do, but the reasons are sufficient. However, I will try and get a statement from my -- superiors -- which may satisfy you and perhaps placate the Freedom League. Now, please, can we return to the agenda and start recording again?"

"You know why Wainwright and his type fear me, don't you?" asked Karellen. His voice was somber now, like a great organ rolling its notes from a high cathedral nave. "You will find men like him in all the world's religions. They know that we represent reason and science, and however confident they may be in their beliefs, they fear that we will overthrow their gods. Not necessarily through any deliberate act, but in a subtler fashion. Science can destroy religion by ignoring it as well as by disproving its tenets. No one ever demonstrated, so far as I am aware, the nonexistence of Zeus or Thor, but they have few followers now. The Wainwrights fear, too, that we know the truth about the origins of their faiths. How long, they wonder, have we been observing humanity? Have we watched Mohammed begin the Hegira, or Moses giving the Jews their laws? Do we know all that is false in the stories they believe?"

"And how much is that?"

"I don't know," Stormgren replied wearily as he threw the files down on his desk and collapsed into the seat. "Karellen's consulting his superiors now, whoever or whatever they may be. He won't make any promises."

"Well?" asked Van Ryberg anxiously. "Did you have any luck?"

"Listen," said Pieter abruptly, "I've just thought of something. What reason have we for believing that there is anyone beyond Karellen? Suppose all the Overlords, as we've christened them, are right here on Earth in these ships of theirs? "They may have nowhere else to go, but they're hiding the fact from us."

"It's an ingenious theory," grinned Stormgren. "But it clashes with what little I know -- or think I know -- about Karellen's background."

"Well, he often refers to his position here as something temporary, hindering him from getting on with his real work, which I think is some form of mathematics. Once I mentioned Acton's quotation about power corrupting, and absolute power corrupting absolutely. I wanted to see how he'd react to that. He gave that cavernous laugh of his, and said; 'There's no danger of that happening to me. In the first case, the sooner I finish my work here, the sooner I can get back to where I belong, a good many light-years from here. And secondly, I don't have absolute power, by any means. I'm just -- Supervisor.' Of course, he may have been misleading me. I can never be sure of that."

Van Ryberg grinned, a little sheepishly.

"He's immortal isn't he?"

"Yes, by our standards, though there's something in the future he seems to fear; I can't imagine what it is. And that's really all I know about him."

"It isn't very conclusive. My theory is that his little fleet's lost in space and is looking for a new home. He doesn't want us to know how few he and his comrades are. Perhaps all those other ships are automatic, and there's no-one in any of them. They're just an imposing faзade."

"You," said Stormgren, "have been reading too much science-fiction."

"Your explanation, as usual, is much too ingenious to be true. Though we can only infer its existence, there must be a great civilization behind the Supervisor -- and one that's known about man for a very long time. Karellen himself must have been studying us for centuries. Look at his command of English, for example. He taught me how to speak it idiomatically!"

Stormgren shook his head in amused disagreement.

"The 'Invasion From Space' didn't turn out quite as expected, did it? My theory would certainly explain why Karellen never shows himself. He doesn't want us to learn that there aren't any more Overlords."

"Oh yes, quite often -- but only on trivial points. I think he has an absolutely perfect memory, but there are some things he hasn't bothered to learn. For instance, English is the only language he understands completely, though in the last two years he's picked up a good deal of Finnish just to tease me. And one doesn't learn Finnish in a hurry! He can quote great slabs of the 'Kalevala', whereas I'm ashamed to say I know only a few lines. He also knows the biographies of all living statesmen, and sometimes I can identify the references he's used. His knowledge of history and science seems complete -- you know how much we've already learned from him. Yet, taken one at a time, I don't think his mental gifts are quite outside the range of human achievement. But no man could possibly do all the things he does."

"Have you ever discovered anything he doesn't know?"

"That's more or less what I've decided already," agreed Van Ryberg. "We can argue round Karellen forever, but in the end we always come back to the same question: why the devil won't he show himself? Until he does, I'll go on theorizing and the Freedom League will go on fulminating."

"One dark night, Mr. Supervisor, I hope some reporter takes a rocket up to your ship and climbs in through the back door with a camera. What a scoop that would be!"

He cocked a rebellious eye at the ceiling.

If Karellen was listening, be gave no sign. But, of course, he never did.

In the first year of their coming, the advent of the Overlords had made less difference to the pattern of human life than might have been expected. Their shadow was everywhere, but it was an unobtrusive shadow. Though there were few great cities on Earth where men could not see one of the silver ships glittering against the zenith, after a little while they were taken as much for granted as the sun, moon or clouds. Most men were probably only dimly aware that their steadily rising standards of living were due to the Overlords. When they stopped to think of it -- which was seldom -- they realized that those silent ships had brought peace to all the world for the first time in history, and were duly grateful.

But these were negative and unspectacular benefits, accepted and soon forgotten. The Overlords remained aloof, hiding their faces from mankind. Karellen could command respect and admiration; he could win nothing deeper so long as he pursued his present policy. It was hard not to feel resentment against these Olympians who spoke to man only over the radio-teleprinter circuits at United Nations Headquarters. What took place between Karellen and Stormgren was never publicly revealed, and sometimes Stormgren himself wondered why the Supervisor found these interviews necessary.

Perhaps he felt the need of direct contact with one human being at least; perhaps he realized that Stormgren needed this form of personal support. If this was the explanation, the Secretary-General appreciated it; he did not mind if the Freedom League referred to him contemptuously as "Karellen's office-boy".

The Overlords had never had any dealings with individual states and governments; they had taken the United Nations Organization as they found it, given instructions for installing the necessary radio equipment, and issued their orders through the mouth of the Secretary-General. The Soviet delegate had quite correctly pointed out, at considerable length and upon innumerable occasions, that this was not in accordance with the Charter. Karellen did not seem to worry.

It was amazing that so many abuses, follies and evils could be dispelled by those messages from the sky. With the arrival of the Overlords, nations knew that they need no longer fear each other, and they guessed -- even before the experiment was made -- that their existing weapons were certainly impotent against a civilization that could bridge the stars. So at once the greatest single obstacle to the happiness of mankind had been removed.

The Overlords seemed largely indifferent to forms of government, provided that they were not oppressive or corrupt. Earth still possessed democracies, monarchies, benevolent dictatorships, communism and capitalism. This was a source of great surprise to many simple souls who were quite convinced that theirs was the only possible way of life. Others believed that Karellen was merely waiting to introduce a system that would sweep away all existing forms of society, and so had not bothered with minor political reforms. But this, like all other speculations concerning the Overlords, was pure guesswork. No one knew their motives; and no one knew towards what future they were shepherding mankind.