Number 1 edit
January 1940
Cover art by Robert Fuqua
- Sons of the Deluge [Part 1 of 2] • Nelson S. Bond • novella
- Adam Link in Business [Adam Link] • Eando Binder • novelette (© Copyright Renewed: details pending.)
- The Strange Death of Richard Sefton • Carl Selwyn • short story
- The Man Who Saw Two Worlds [Brutus Lloyd] • Thornton Ayre • novelette
- Slaves of Rhythm [Chance Martin] • Frederic Arnold Kummer • short story
- Dr. Varsag's Experiment • Lee Rogow • novelette
Number 2 edit
February 1940
Cover art by C. L. Hartman
- Adam Link's Vengeance [Adam Link] • Eando Binder • novelette (© Copyright Renewed: details pending.)
- Rockets Over Europe [Martin Langley] • Robert Moore Williams • short story
- Undersea Prisoner • Harl Vincent • novelette
- Truth Is a Plague! • David Wright O'Brien • novelette
- The Thirteenth Mr. Tumps • Richard O. Lewis • short story
- Sons of the Deluge [Part 2 of 2] • Nelson S. Bond • novella
Number 3 edit
March 1940
Cover art by H. W. McCauley
- Black World [Part 1 of 2] • Raymond A. Palmer • novella
- The Strange Voyage of Dr. Penwing [Doctor Penwing] • Richard O. Lewis • short story
- Paul Revere and the Time Machine [Time Swing] • A. W. Bernal • novelette
- Vagabonds of the Void • Peter Horn • novelette
- The Scientific Pioneer [Horsesense Hank] • Nelson S. Bond • short story
- Terror Out of the Past • Raymond Z. Gallun • novelette
Number 4 edit
April 1940
Cover art by H. R. Hammond
- The Case of the Murdered Savants [Brutus Lloyd] • Thornton Ayre • novelette
- Fish Men of Venus • David Wright O'Brien • novelette
- War of the Scientists • John Russell Fearn • novelette
- Revolt of the Ants • Milton Kaletsky • short story
- Black World [Part 2 of 2] • Raymond A. Palmer • novella
- When the Ice Terror Came • Jack West • short story
Number 5 edit
May 1940
Cover art by C. L. Hartman
- The Time-Wise Guy • Ralph Milne Farley • incomplete
- Giants Out of the Sun • Peter Horn • novelette
- Adam Link, Robot Detective [Adam Link] • Eando Binder • novelette (© Copyright Renewed: details pending.)
- Liline, the Moon Girl • Edmond Hamilton • novelette
- Hok Draws the Bow [Hok] • Manly Wade Wellman • novelette
- John Brown's Body (O'Brien & McGivern) • David Wright O'Brien & Wm. P. McGivern • short story
Number 6 edit
June 1940
Cover art by Julian S. Krupa
- Slave Raiders from Mercury [Lester Allison] • Don Wilcox • novella
- Warlords of Mars [Don Hargeaves] • Festus Pragnell • novelette
- The Time-Wise Guy • Ralph Milne Farley • short story
- Trapped on Titan • David Wright O'Brien • novelette
- The Mathematical Kid [Georgie Periwinkle] • Ross Rocklynne • short story (© Copyright Renewed: details pending.)
- Treachery on Planetoid 41 • Floyd Gale • short story
- Planet of Black Terror • Ed Earl Repp • novelette
Number 7 edit
July 1940
Cover art by Robert Fuqua
- When the Gods Make War • Raymond A. Palmer • novelette
- Adam Link, Champion Athlete [Adam Link] • Eando Binder • novelette (© Copyright Renewed: details pending.)
- Mirrors of Madness • Don Wilcox • novelette
- The Monster Out of Space • Malcolm Jameson • novelette
- The Ray of Hypnosis [Homer Higginbottom] • Milton Kaletsky • short story
- Secret of the Moon Treasure • Thornton Ayre • novelette
Number 8 edit
August 1940
Cover art by Julian S. Krupa & Leo Morey
- Suicide Squadrons of Space • David Wright O'Brien • novelette
- The Incredible Theory of Dr. Penwing [Doctor Penwing] • Richard O. Lewis • novelette
- The Living Mist • Ralph Milne Farley • novelette
- Lost Treasure of Mars • Edmond Hamilton • short story
- Murder in the Time World • Malcolm Jameson • novelette
- Mystery of the Mind Machine • Don Wilcox • novelette
- The Man Who Knew All the Answers • Donald Bern • short story
Number 9 edit
September 1940
Cover art by Robert Fuqua
- Fifth Column of Mars • Robert Moore Williams • novelette
- Champlin Fights the Purple God • Don Wilcox • novella
- X-Ray Murder • Milton Kaletsky • short story
- The Man Who Never Lived • Ross Rocklynne • short story (© Copyright Renewed: details pending.)
- Blitzkrieg—1950! • Frederic Arnold Kummer • novelette
- The Synthetic Woman • Jep Powell • novelette
Number 10 edit
October 1940
Cover art by Leo Morey
- Raiders Out of Space • Robert Moore Williams • novelette
- Rescue Into the Past • Ralph Milne Farley • short story
- The Invisible World • Ed Earl Repp • novelette
- The Day Time Stopped Moving • Bradner Buckner • short story
- The Voyage That Lasted 600 Years • Don Wilcox • novelette
- Revolt on Io • Jack West • novelette
Number 11 edit
November 1940
Cover art by Robert Fuqua
- West Point, 3000 A.D. [Part 1 of 2] • Manly Wade Wellman • novella
- Treasure Trove in Time • David Wright O'Brien • short story
- Revolt on the Tenth World • Edmond Hamilton • novelette
- The Scientific Pioneer Returns [Horsesense Hank; Lancelot Biggs] • Nelson S. Bond • novelette
- Hell Ship of Space • Frederic Arnold Kummer • novelette
- The Achilles Heel • Raymond Z. Gallun • short story
Number 12 edit
December 1940
Cover art by Robert Fuqua
- Adam Link Fights a War [Adam Link] • Eando Binder • novelette (© Copyright Renewed: details pending.)
- Priestess of the Moon • Ray Cummings • novelette
- The Planet of Errors • Milton Kaletsky • short story
- The Visible Invisible Man • William P. McGivern • novelette
- Three Wise Men from Space • Donald Bern • short story
- West Point, 3000 A.D. [Part 2 of 2] • Manly Wade Wellman • novella