The staff man on duty had gone to the installation's kitchen for a cup of coffee. No sound originated in the room, unless one counted the fluttering of a piece of weighted-down paper on the desk. Outside, palm trees whispered and rustled their long fronds in the southeast trade wind under a sky full of glittering stars. Beyond, there was the dull booming of surf upon the barrier reef of the island. But the instruments made no sound. Only the tape reels moved. The signals began abruptly. They came out of a speaker and were instantly recorded. They were elfin and flutelike and musical. They were crisp and distinct. They did not form a melody, but nearly all the components of melody were there. Pure musical notes, each with its own pitch, all of different lengths, like quarter-notes and eighth-notes in music. The sounds needed only rhythm and arrangement to form a plaintive tune. Nothing happened. The sounds continued for something over a minute. They stopped long enough to seem to have ended. Then they began again. When the staff man came back into the room with a coffee cup in his hand, he heard the flutings instantly. His jaw dropped. He said, "What the hell?" and went to look at the instruments. He spilled some of his coffee when he saw their readings. The tracking dials said that the signals came from a stationary source almost directly overhead. If they were from a stationary source, no plane was transmitting them. Nor could they be coming from an artificial satellite. A plane would move at a moderate pace across the sky. A satellite would move faster. Much faster. This source, according to the instruments, did not move at all. The staff man listened with a blank expression on his face. There was but one rational explanation, which he did not credit for an instant. The reasonable answer would have been that somebody, somewhere, had put a satellite out into an orbit requiring twenty-four hours for a circuit of the earth, instead of the ninety to one-hundred-twenty-four-minute orbits of the satellites known to sweep around the world from west to east and pole to pole. But the piping, musical sounds were not the sort of thing that modern physicists would have contrived to carry information about cosmic-particle frequency, space temperature, micrometeorites, and the like. The signals stopped again, and again resumed. The staff man was galvanized into activity. He rushed to waken other members of the outpost. When he got back, the signals continued for a minute and stopped altogether. But they were recorded on tape, with the instrument readings that had been made during their duration. The staff man played the tape back for his companions. They felt as he did. These were signals from space where man had never been. They had listened to the first message ever to reach mankind from the illimitable emptiness between the stars and planets. Man was not alone. Man was no longer isolated. Man....