March 1967. Cover art by John Schoenherr illustrating “The Time-Machined Saga” (serial, part 1 of 3) by Harry Harrison. ALSO: “Radical Center” by Mack Reynolds; “In the Shadow” by Poul Anderson [as by Michael Karageorge]; plus stories by Richard Anvil and R. C. FitzPatrick. FEATURES: Editorial by John W. Campbell; science essay: " Countdown for Surveyor “ by Joseph Green; The Reference Library (book reviews) by P. Schuyler Miller, Brass Tacks (letters). Interior artwork by: Leo Summers, Kelly Freas. Magazine editor: John W. Campbell.