He waited for the full meaning of his words to strike home. Then, speaking slowly and carefully, he gave to both Lys and Diaspar the knowledge that had been won from the a mind of Vanamonde.

It was not even true that Man had reached the stars. The whole of his little empire was bounded by the orbits of Pluto and Persephone, for interstellar space proved a barrier beyond his power to cross. His entire civilization was huddled around the sun, and was still very young when-the stars reached him.

The impact must have been shattering. Despite his failures, Man had never doubted that one day he would conquer the depths of space. He believed too that if the Universe held his equals, it did not hold his superiors. Now he knew that both beliefs were wrong, and that out among the stars were minds far greater than his own. For many centuries, first in the ships of other races and later in machines built with borrowed knowledge, Man had explored the Galaxy. Everywhere he found cultures he could understand but could not match, and here and there he encountered minds which would soon have passed altogether beyond his comprehension.

The shock was tremendous, but it proved the making of the race. Sadder and infinitely wiser, Man had returned to the Solar System to brood upon the knowledge he had gained., He would accept the challenge, and slowly he evolved a plan which gave hope for the future.

Once the physical sciences had been Man’s greatest interest. Now he turned even more fiercely to genetics and the study of the mind. Whatever the cost, he would drive himself to the limits of his evolution.

The great experiment had consumed the entire energies of the race for millions of years. All that striving, all that sacrifice and toil, became only a handful of words in Callitrax’s narrative. It had brought Man his greatest victories.

He had banished disease; he could live forever if he wished, and in mastering telepathy he had bent the most subtle of all powers to his will.

He was ready to go out again, relying upon his own resources, into the great spaces of the Galaxy. He would meet as an equal the races of the worlds from which he had once turned aside. And he would play his full part in the story of the Universe.

These things he did. From this age, perhaps the most spacious of all history, came the legends of the Empire. It had been an Empire of many races, but this had been forgotten in the drama, too tremendous for tragedy, in which it had come to its end.

The Empire had lasted for at least a million years. It must have known many crises, perhaps even wars, but all these were lost in the sweep of great races moving together toward maturity.

«We can be proud,» continued Callitrax, «of the part our ancestors played in this story. Even when they had reached their cultural plateau, they lost none of their initiative. We deal now with conjecture rather than proved fact, but it seems certain that the experiments which were at once the Empire’s downfall and its crowning glory were inspired and directed by Man.

«The philosophy underlying these experiments appears to have been this. Contact with other species had shown Man how profoundly a race’s world-picture depended upon its physical body and the sense organs with which it was equipped. It was argued that a true picture of the Universe could be attained, if at all, only by a mind that was free from such physical limitations-a pure mentality, in fact. This was a conception common among many of Earth’s ancient religious faiths, and it seems strange that an idea which had no rational origin should finally become one of the greatest goals of science.

«No disembodied intelligence had ever been encountered in the natural Universe; the Empire set out to create one. We have forgotten, with so much else, the skills and knowledge that made this possible. The scientists of the Empire had mastered all the forces of Nature all the secrets of time and space. As our mind’s are the by-product of an immensely intricate arrangement of brain cells, linked together by the network of the nervous system, so they strove to create a brain whose components were not material, but patterns embossed upon space itself. Such a brain if one can call it that, would use electrical or yet higher forces for its operation, and would be completely free from the tyranny of matter. It could function with far greater speed than any organic intelligence; it could endure as long as there was an erg of free energy left in the Universe, and no limit could be seen for its powers. Once created, it would develop potentialities which even its makers could not foresee.

«Largely as a result of the experience gained in his own regeneration, Man suggested that the creation of such beings should be attempted. It was the greatest challenge ever thrown out to intelligence in the Universe, and after centuries of debate it was accepted. All the races of the Galaxy joined together in its fulfillment.

«More than a million years were to separate the dream from the reality. Civilizations were to rise and fall, again and yet again the age-long toil of worlds was to be lost, but the goal was never forgotten. One day we may know the full story of this, the greatest sustained effort in all history. Today we only know that its ending was a disaster that almost wrecked the Galaxy.

«Into this period Vanamonde’s mind refuses to go. There is a narrow region of time which is blocked to him; but only, we believe, by his own fears. At its beginning we can see the Empire at the summit of its glory, taut with the expectation of coming success. At its end, only a few thousand years later, the Empire is shattered and the stars themselves are dimmed as though drained of their power. Over the Galaxy hangs a pall of fear, a fear with which is linked the name: ‘The Mad Mind.’

«What must have happened in that short period is not hard to guess. The pure mentality had been created, but it was either insane, or as seems more likely from other sources, was implacably hostile to matter. For centuries it ravaged the Universe until brought under control by forces at which we cannot guess. Whatever weapon the Empire used in its extremity squandered the resources of the stars; from the memories of that conflict spring some, though not all, of the legends of the Invaders. But of this I shall presently say more.»

«The Mad Mind could not be destroyed, for it was immortal. It was driven to the edge of the Galaxy and there imprisoned in a way we do not understand. Its prison was a strange artificial star known as the Black Sun, and there it remains to this day. When the Black Sun dies, it will be free again. How far in the future that day lies there is no way of telling.»

Callitrax became silent, as if lost in his own thoughts, utterly unconscious of the fact that the eyes of all the world were upon him. In the long silence, Alvin glanced over the packed multitude around him, seeking to read their minds as they faced this revelation-and this unknown threat which must now replace the myth of the Invaders. For the most part, the faces of his fellow citizens were frozen in disbelief; they were still struggling to reject their false past, and could not yet accept the yet stranger reality that had superseded it.

Callitrax began to speak again in a quiet, more subdued voice as he described the last days of the Empire. This was the age Alvin realized as the picture unfolded before him, in which he would have like to have lived. There had been adventure then, and a superb and dauntless courage-the courage that could snatch victory from the teeth of disaster.

«Though the Galaxy had been laid waste by the Mad Mind, the resources of the Empire were still enormous, and its spirit was unbroken. With a courage at which we can only marvel, the great experiment was resumed and a search made for the flaw that had caused the catastrophe. There were now, of course, many who opposed the work and predicted further disasters, but they were overruled. The project went ahead and, with the knowledge so bitterly gained, this time it succeeded.