Cadwalader Ringgold:
Sentinels From Space - Eric Frank Russell
Cadwalader Ringgold:
Invaders of Earth - Edited by Groff Conklin
Cadwalader Ringgold:
The Martian Chronicles - Ray Bradbury
Cadwalader Ringgold:
Mission of Gravity - Hal Clements
Cadwalader Ringgold:
Tomorrow Times Seven - Frederik Pohl
Cadwalader Ringgold:
Mysterious Planet - Lester del Rey
Cadwalader Ringgold:
Puppet Masters - 1st paperback - Robert A. Heinlein
Cadwalader Ringgold:
Puppet Masters - back cover - 1st paperback - Robert A. Heinlein
Cadwalader Ringgold:
Untouched By Human Hands - Robert Sheckley
Cadwalader Ringgold:
Trouble on Titan - Alan E. Nourse - cover artist Ed Valigursky