10 • Raiders Out of Space • (1940) • novelette by Robert Moore Williams

34 • Rescue Into the Past • (1940) • short story by Ralph Milne Farley

48 • The Invisible World • (1940) • novelette by Ed Earl Repp

68 • Scientific Mysteries: The Fate of the Mammoth • [Scientific Mysteries] • (1940) • essay by Joseph J. Millard

70 • The Day Time Stopped Moving • (1940) • short story by Ed Earl Repp [as by Bradner Buckner]

82 • The Voyage That Lasted 600 Years • (1940) • novelette by Don Wilcox

106 • Revolt on Io • (1940) • novelette by Jack West

131 • Meet the Authors: Jack West • (1940) • essay by Jack West

144 • Life on Ganymede • (1940) • essay by unknown [as by Henry Gade]

12 • West Point, 3000 A.D. (Part 1 of 2) • (1940) • serial by Manly Wade Wellman (book publication as West Point 3000 A.D.)

44 • Treasure Trove in Time • (1940) • short story by David Wright O'Brien

58 • Scientific Mysteries: The Mystery of the Moon • [Scientific Mysteries] • (1940) • essay by Joseph J. Millard

60 • Revolt on the Tenth World • (1940) • novelette by Edmond Hamilton

88 • The Scientific Pioneer Returns • [Lancelot Biggs • 6] • (1940) • novelette by Nelson S. Bond

108 • Hell Ship of Space • (1940) • novelette by Frederic Arnold Kummer, Jr.

123 • The First Science Fiction Story • (1940) • essay by Simpson M. Ritter

124 • The Achilles Heel • (1940) • short story by Raymond Z. Gallun

138 • Meet the Authors: David Wright O'Brien • (1940) • essay by David Wright O'Brien

144 • Life on Titan • (1940) • essay by unknown [as by Henry Gade]

10 • Adam Link Fights a War • [Adam Link] • (1940) • novelette by Otto Binder [as by Eando Binder]

42 • Priestess of the Moon • (1940) • novelette by Ray Cummings

70 • The Planet of Errors • (1940) • short story by Milton Kaletsky

74 • The Visible Invisible Man • (1940) • novelette by William P. McGivern

98 • Scientific Mysteries: Bomb Sight of the Gods • [Scientific Mysteries] • (1940) • essay by Joseph J. Millard

101 • Clouds in Space • (1940) • essay by Morrison Colladay

102 • Three Wise Men from Space • short story by Albert Bernstein (variant of Three Wise Men of Space 1940) [as by Donald Bern]

108 • West Point, 3000 A.D. (Part 2 of 2) • (1940) • serial by Manly Wade Wellman (book publication as West Point 3000 A.D.)

133 • Meet the Authors: Donald Bern • (1940) • essay by Albert Bernstein [as by Donald Bern]

144 • A City on Mars • (1940) • essay by unknown [as by Henry Gade]