The Monkey Wrench - short story by Gordon R. Dickson
The First Men - novelette by Howard Fast
Counterfeit - novelette by Alan E. Nourse
The Greater Thing - novelette by Tom Godwin
Build Up Logically - short story by Howard Schoenfeld (variant of Built Up Logically 1949)
The Liberation of Earth - short story by William Tenn
An Alien Agony - short story by Harry Harrison (variant of The Streets of Ashkelon)
The Tunnel Under the World - novelette by Frederik Pohl
The Store of the Worlds - short story by Robert Sheckley
Jokester - short story by Isaac Asimov
Pyramid - novelette by Robert Abernathy
The Forgotten Enemy - short story by Arthur C. Clarke