He dreamed it three nights running, then it stopped, for awhile. Then, a week later, he had the dream again, repeated in every detail. He had it a dozen times before he was twelve, and as many more before he was thirteen. It recurred at random intervals all through his teens, while he was in college, and after. When he grew up he found out that recurrent dreams are by no means unusual. But this was very far from a usual dream. From time to time, he observed new details in the dream. He knew that he was dreaming. His actions and his emotion did not vary, but he was able to survey them--like the way one can take note of items in a book one reads while quite absorbed in it. He came to notice the way the trees sent their roots out over the surface of the ground before dropping suckers down into it. He noticed a mass of masonry off to the left. He discovered that a hill in the distance was not a natural hill. He was able to remember markings on the large, stationary moon in the sky, and to realize that the smaller one was jagged and irregular in shape. The dream did not change, but his knowledge of the place of the dream increased. As he grew older, he was startled to realize that though the trees, for example, were not real, they were consistent with reality. The weapon he held in his hand was especially disturbing. Its grip and barrel were transparent plastic, and in the barrel there was a sequence of peculiarly-shaped forms, in and about which wire had been wound. As a grown man he'd made such shapes in metal, once. He'd tried them out as magnets in a job for American Tool. But they weren't magnets. They were something specific and alarming instead. He also came to know exactly what the mass of masonry was, and it was a sober engineering feat. No boy of eleven could have imagined it. And always there were the flutelike musical sounds coming from behind him. When he was twenty-five he'd memorized them. He'd heard them--dreamed them--hundreds of times. He tried to duplicate them on a flute and devised a special mute to get exactly the tone quality he remembered so well. He made a recording to study, but the study was futile. In a way, it was unwholesome to be so much obsessed by a dream. In a way, the dream was magnificently irrelevant to messages transmitted through millions of miles of emptiness. But the flutelike sounds linked it--now--to reality! He paced up and down in the empty, resonant building and muttered, "I ought to talk to the space-exploration people."