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

The Rival Rigelians / Nebula Alert

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

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

Ace Double. Nebula Alert A Bertram Chandler. Rival Rigelians Mack Reynolds. 1967

NEBULA ALERT (A. Bertram Chandler)/THE RIVAL RIGELIANS (Mack Reynolds) 1967 Ace

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

Mack Reynolds - The Rival Rigelians & A Bertram Chandler - Nebula Alert Ace 1967