PUBLICATION HISTORY Analog, September 1968, p.62-76. Illustrated by Leo Summers. Prime Number, July 1970. Analog 8, edited by John W. Campbell. New York: Doubleday, 1971, hbk. as: "Beobachtunsgabe" in Primzhal [Prime Number]. June 1972. [German]. Analog: the Best of Science Fiction. New York: A&W / Galahad, July 1985, p.529-539, ISBN: 0-88365-637-X, hbk. Tin Stars, edited by Isaac Asimov, Martin H. Greenberg and Charles Waugh. New York: Signet, 1986. p.109-125.