Contents (view Concise Listing)

• 9 • Introduction (Science-Fiction Adventures in Mutation) • essay by Groff Conklin
• 17 • Chain of Command • (1954) • short story by Stephen Arr
• 26 • Battle of the Unborn • (1950) • short story by James Blish (variant of Struggle in the Womb)
• 33 • The Hungry Guinea Pig • (1930) • novelette by Miles J. Breuer, M.D.
• 55 • Keep Out • (1954) • short story by Fredric Brown
• 59 • The Small World of M-75 • (1954) • short story by Ed M. Clinton, Jr.
• 72 • Limiting Factor • (1954) • short story by Theodore R. Cogswell
• 83 • The Lysenko Maze • (1953) • short story by Donald A. Wollheim [as by David Grinnell]
• 94 • The Patient • (1943) • short story by E. Mayne Hull
• 100 • Cold War • [Hogben • 5] • (1949) • novelette by Henry Kuttner and C. L. Moore [as by Henry Kuttner]
• 125 • Skag with the Queer Head • (1951) • short story by Murray Leinster
• 143 • Veiled Island • (1946) • novelette by Emmett McDowell
• 186 • Experiment Station • short story by Kris Neville
• 196 • Family Resemblance • (1953) • short story by Alan E. Nourse
• 207 • And Thou Beside Me • (1954) • short story by Mack Reynolds
• 214 • This One's on Me • (1953) • short story by Eric Frank Russell
• 221 • Age of Prophecy • (1951) • novelette by Margaret St. Clair
• 249 • The Love of Heaven • (1948) • short story by Theodore Sturgeon
• 263 • The Impossible Voyage Home • (1954) • novelette by F. L. Wallace
• 285 • The Conspirators • (1954) • novelette by James White
• 310 • The Better Choice • short story by S. Fowler Wright
• 313 • Selected List of Tales About Mutants and Changelings • essay by Groff Conklin