The Rival Rigelians / Planetary Agent X by Mack Reynolds

THE RIVAL RIGELIANS / PLANETARY AGENT X by Mack Reynolds 1967 Ace

THE RIVAL RIGELIANS / PLANETARY AGENT X by Mack Reynolds 1967 Ace paperback

Mack Reynolds, THE RIVAL RIGELIANS and PLANETARY AGENT X, Vintage 1960's SF PB

Ace Books Planetary Agent X / Behold the Stars Reynolds Bulmer Sci-Fi

Planetary Agent X / Behold the Stars by Mack Reynolds / K Bulmer - Ace Double

Ace Double Planetary Agent X Mack Reynolds Behold the Stars Kenneth Bulmer

Planetary Agent X / Behold the Stars by Mack Reynolds / K Bulmer - Ace Double