51 books • 4 series
Seetee Sun (John Russell Fearn's The Golden Amazon, #28)
The Crimson Peril (John Russell Fearn's The Golden Amazon, #23)
Sphero Nova
Cosmic Echelon
This Second Earth
Satellite B.C.
Dark Andromeda
Time and Space
Dark Centauri
The World Makers
Zenith-D
No Dawn and No Horizon
The Dark Millenium
Barrier Unknown
When The Gods Came
Zero Point
Twilight Zone
The Time Kings
Alien
Edge of Eternity
Black Abyss
Day of the Beasts
Space Void
Hydrosphere