The Secret of the Ninth Planet
Donald A. Wollheim
The Secret of the Martian Moons
Secret of the Martian Moons
The Secret of Saturn's Rings
More Adventures on Other Planets
Men on the Moon
The Mask of Demeter
C. M. Kornbluth & Donald A. Wollheim
The Martian Missile
The Man from the Future
Interplane Express
Donald A. Wollheim & C. M. Kornbluth
The Hidden Planet
AceD354 (1)
Edge of Time
The Earth in Peril
The Earth in Peril / Who Speaks of Conquest?
Donald A. Wollheim & Lan Wright
Destiny's Orbit
Ajax Calkins (1)