through the sucking sand with strength summoned from a well of energy within his body that had never been there before.

Through the thin glassite walls of his helmet he could hear the thuk, thuk, thuk of his boots as they pounded somewhere below him, and there was another pounding, a deadly rhythmic bursting pressure in his chest. And a whine in his ears....

The wind-strewn sand stretched flat and infinitely before him. Then leaped at him headlong and there was no horizon; there was only the sudden awful wrench of concussion, a tremor of pure sound which would, in denser atmosphere, have destroyed him with the inertia of his own body.

He could not move. Only cling to the shifting desert floor that rocked sickeningly beneath his outstretched body ... cling to it for dear life.

There was no thought, no understanding. Only a sensation which he could not comprehend, and the sure knowledge that none of this was real. Not real, but the end of survival nonetheless.

Pain, and seeing two bright objects transiting the darkness at which he looked; seeing something then between.

His brain began identifying. The darkness; sky. The bright objects; Diemos, Phobos.... And the something between—

It was a transparency of some sort; curved, or he would not have been able to detect it at all. A vaulted ceiling through which he could see....

His full consciousness came flooding back, then. He tried the muscles in his neck, they hurt, but they worked, and he could move his head from side to side. There was the same transparency, as though he were covered by some huge, invisible bowl.

And there were men. Big, muscular creatures, yet thin, tall.... Not like the others at all....

He sat bolt upright, and they did not move. It was not the same as before. No small room. No voice that he could not see. They had not even removed his suit or his helmet, and he was lying on a hard, cold substance.

Then he saw what they were doing. There were two of them apart from the others, working to bring a compact-looking machine into position near him. A gleaming, short cylinder, swung on gymbals between slender forks, mounted on a thin wheeled standard. They were aiming it at him.

"No! No—" He tried to get to his knees, but it was as though there were no muscles in his body.

"Man of—Earth! We are friendly. Is that understood?"

The thought-words formed in his brain as the strange images had before, and then he knew. Should have guessed it, part of his mind was telling him in a fantastically detached way, the dreams ... the compulsions over which he had had no control in the ship.... This—thing. It probably—

"You are quite astute, Earthman. But it is not our technology which created this device. To save you and the civilization which you represent—and ultimately, our own—it was necessary for us to steal it. It cost six lives."

"Steal...."

"From your former captors. It is their invention, as are so many things with which they destroy. With this instrument, they have succeeded in taking one of Nature's more subtle phenomenon—psychokinesis—and amplifying its energies nearly a million-fold. Those stepped-up energies can then be projected in a tight or fanned beam at will.

"They can make a man 'dream,' as you did—or they can destroy him outright, depending on which of the 'psi' factors, ESP or PK, is given dominance during projection. But we are not skilled in its operation—they detected our use of it on you while you slept, and from that moment on you were so well screened that even at the risk of burning this unit out, we were not able to project powerfully enough to do more than merely touch your brain—"

There was a strange calm in his mind, now. He understood the words and accepted them as matter-of-factly as they were given. Even now they were manipulating him like some intangible puppet, yet he was convinced it was not a malevolent manipulation.