Worlds to come

Conjectures what man's future explorations will reveal: The Sentinel, by A. C. Clarke; Moonwalk, by H. B. Fyfe; Mars is Heaven, by R. Bradbury; The Edge of the Sea, by A. Budrys; The Martian Way, by I. Asimov; The Big Contest, by J. D. MacDonald; Ordeal in Space, by R. A. Heinlein; That Share of Glory, by C. M. Kornbluth; and Sunken Universe, by J. Blish.