Part Six: 1935 - essay by Isaac Asimov
The Parasite Planet - novelette by Stanley G. Weinbaum (variant of Parasite Planet)
Proxima Centauri - novella by Murray Leinster
The Accursed Galaxy - short story by Edmond Hamilton
Part Seven: 1936 - essay by Isaac Asimov
He Who Shrank - novella by Henry Hasse
The Human Pets of Mars - novella by Leslie F. Stone [as by Leslie Francis Stone]
The Brain Stealers of Mars - short story by John W. Campbell, Jr.
Devolution - short story by Edmond Hamilton
Big Game - short story by Isaac Asimov
Part Eight: 1937 - essay by Isaac Asimov
Other Eyes Watching - essay by John W. Campbell, Jr.
Minus Planet - novelette by John D. Clark, Ph.D.
Past, Present and Future - novelette by Nat Schachner
Part Nine: 1938 - essay by Isaac Asimov
The Men and the Mirror - novelette by Ross Rocklynne
