'The Atomic Power Plant.'

'Had he finished his experiment?'

The Boss shrugged: There's no way of telling. He was dead when we found him.'

Boulder 's lips were pinched and colorless. 'That must be determined, somehow. A commission of scientists must be established, and, if necessary, the experiment must be repeated -'

But the Boss just looked at him, and reached for a cigar. I've never seen him take longer - and when he put it down, curled in its unused smoke, he said: 'Tywood wrote an article for a magazine, twenty years ago -'

'Oh,' and the professor's lips twisted, 'is that what gave you your clue? You may ignore that. The man is only a physical scientist and knows nothing of either history or sociology. A schoolboy's dreams and nothing more.'

'Then, you don't think sending your translation back will inaugurate a Golden Age, do you?'

'Of course not. Do you think you can graft the developments of two thousand years of slow labor onto a child society not ready for it? Do you think a great invention or a great scientific principle is born full-grown in the mind of a genius divorced from his cultural milieul Newton's enunciation of the Law of Gravity was delayed for twenty years because the then-current figure for the Earth's diameter was wrong by ten percent. Archimedes almost discovered calculus, but failed because Arabic numerals, invented by some nameless Hindu or group of Hindus, was unknown to him.

'For that matter, the mere existence of a slave society in ancient Greece and Rome meant that machines could scarcely attract much attention - slaves being so much cheaper and more adaptable. And men of true intellect could scarcely be expected to spend their energies on devices intended for manual labor. Even Archimedes, the greatest engineer of antiquity, refused to publish any of his practical inventions - only mathematic abstractions. And when a young man asked Plato of what use geometry was, he was forthwith expelled from the Academy as a man with a mean, unphilosophic soul.

'Science does not plunge forward - it inches along in the directions permitted by the greater forces that mold society and which are in turn molded by society. And no great man advances but on the shoulders of the society that surrounds him-'

The Boss interrupted him at that point. 'Suppose you tell us what your part in Tywood's work was, then. We'll take your word for it that history cannot be changed.'

'Oh it can, but not purposefully - You see, when Tywood first requested my services in the matter of translating certain textbook passages into Greek, I agreed for the money involved. But he wanted the translation on parchment; he insisted on the use of ancient Greek terminology - the language of Plato, to use his words - regardless of how I had to twist the literal significance of passages, and he wanted it hand-written in rolls.

'I was curious. I, too, found his magazine article. It was difficult for me to jump to the obvious conclusion, since the achievements of modern science transcend the imaginings of philosophy in so many ways. But I learned the truth eventually, and it was at once obvious that Tywood's theory of changing history was infantile. There are twenty million variables for every instant of time, and no system of mathematics - no mathematic psychohistory, to coin a phrase - has yet been developed to handle that ocean of varying functions.

'In short, any variation of events two thousand years ago would change all subsequent history, but in no predictable way.'

The boss suggested, with a false quietness: 'Like the pebble that starts the avalanche, right?'

'Exactly. You have some understanding of the situation, I see. I thought deeply for weeks before I proceeded, and then I realized how I must act - must act.'

There was a low roar. The Boss stood up and his chair went over backward. He swung around his desk, and he had a hand on Boulder 's throat. I was stepping out to stop him, but he waved me back -

He was only tightening the necktie a.little. Boulder could still breathe. He had gone very white, and for all the time that the Boss talked, he restricted himself to just that - breathing.

And the Boss said: 'Sure, I can see how you decided you must act. I know that some of you brain-sick philosophers think the world needs fixing. You want to throw the dice again and see what turns up. Maybe you don't even care if you're alive in the new setup - or that no one can possibly know what you've done. But you're going to create, just the same. You're going to give God another chance, so to speak.

'Maybe I just want to live - but the world could be worse. In twenty million different ways, it could be worse. A fellow named Wilder once wrote a play called The Skin of Our Teeth. Maybe you've read it. It's thesis was that Mankind survived by just that skin of their teeth. No, I'm not going to give you a speech about the Ice Age nearly wiping us out. I don't know enough. I'm not even going to talk about the Greeks winning at Marathon; the Arabs being defeated at Tours; the Mongols turning back at the last minute without even being defeated -because I'm no historian.

'But take the Twentieth Century. The Germans were stopped at the Marne twice in World War I. Dunkirk happened in World War II, and somehow the Germans were stopped at Moscow and Stalingrad. We could have used the atom bomb in the last war and we didn't, and just when it looked as if both sides would have to, the Great Compromise happened - just because General Bruce was delayed in taking off from the Ceylon airfield long enough to receive the message directly. One after the other, just like that, all through history - lucky breaks. For every "if" that didn't come true that would have made wonder-men of all of us if it had, there were twenty "ifs" that didn't come true that would have brought disaster to all of us if they had.

'You're gambling on that one-in-twenty chance - gambling every life on Earth. And you've succeeded, too, because Ty-wood did send that text back.'

He ground out that last sentence, and opened his fist, so that Boulder could fall out and back into his chair.

And Boulder laughed.

'You fool,' he gasped, bitterly, 'How close you can be and yet how widely you can miss the mark. Tywood did send his book back, then? You are sure of that?'

'No chemical textbook in Greek was found on the scene,' said the Boss, grimly, 'and millions of calories of energy had disappeared. Which doesn't change the fact, however, that we have two and a half weeks in which to - make things interesting for you.'

'Oh, nonsense. No foolish dramatics, please. Just listen to me, and try to understand. There were Greek philosophers once, named Leucippus and Democritus, who evolved an atomic theory. All matter, they said, was composed of atoms. Varieties of atoms were distinct and changeless and by their different combinations with each other formed the various substances found in nature. That theory was not the result of experiment or observation. It came into being, somehow, full-grown.

'The didactic Roman poet Lucretius, in his "De Rerum Natura," - "On the Nature of Things" - elaborated on that theory and throughout manages to sound startlingly modern.

'In Hellenistic times, Hero built a steam engine and weapons of war became almost mechanized. The period has been referred to as an abortive mechanical age, which came to nothing because, somehow, it neither grew out of nor fitted into its social and economic milieu. Alexandrian science was a queer and rather inexplicable phenomenon.

'Then one might mention the old Roman legend about the books of the Sibyl that contained mysterious information direct from the gods -

'In other words, gentlemen, while you are right that any change in the course of past events, however trifling, would have incalculable consequences, and while I also believe that you are right in supposing that any random change is much more likely to be for the worse than for the better, I must point out that you are nevertheless wrong in your final conclusions.

'Because this is the world in which the Greek chemistry text was sent back.

'This has been a Red Queen's race, if you remember your "Through the Looking Glass." In the Red, Queen's country, one had to run as fast as one could merely to stay in the same place. And so it was in this case! Tywood may have thought he was creating a new world, but it was I who prepared the translations, and I took care that only such passages as would account for the queer scraps of knowledge the ancients apparently got from nowhere would be included.

'And my only intention, for all my racing, was to stay in the same place.'

Three weeks passed; three months; three years. Nothing happened. When nothing happens, you have no proof. We gave up trying to explain, and we ended, the Boss and I, by doubting it ourselves.

The case never ended. Boulder could not be considered a criminal without being considered a world savior as well, and vice versa. He was ignored. And in the end, the case was neither solved, nor closed out; merely put in a file all by itself, under the designation '?' and buried in the deepest vault in Washington.

The Boss is in Washington now; a big wheel. And I'm Regional Head of the Bureau.

Boulder is still assistant professor, though. Promotions are slow at the University.

 The Red Queen's Race,' my fifty-eighth story, was the first to be written by Dr. Asimov.

 In September I began another story, 'Mother Earth,' and submitted it to Campbell on October 12, 1948. After a comparatively small revision of the ending, he took that one, too.