Or All the Seas with Oysters by Avram Davidson, © 1958 by Galaxy Publishing Corp. Appeared originally in Galaxy Science Fiction, May 1958.

The Hell-Bound Train by Robert Bloch, © 1958 by Mercury Press, Inc. Appeared originally in The Magazine of F & SF, September 1958.

The Big Front Yard by Clifford D. Simak. © 1958 by Street & Smith Publications, Inc. Appeared originally in Astounding Science Fiction, October 1958.

Flowers for Algernon by Daniel Keyes, © 1959 by Daniel Keyes. Appeared originally in The Magazine of F & SF, April 1959.

The Longest Voyage by Poul Anderson, © 1960 by Street & Smith Publications, Inc. Appeared originally in Analog Science Fact and Fiction, December 1960.

© 1962 by Isaac Asimov.

Ed. cast.: © 1972 by Ediciones Dronte. Published by arrangement with Doubleday & Company, Inc.