ACE DOUBLE: DAWNMAN PLANET / INHERIT THE EARTH

Ace books, 1967. Cover by Jack Gaughan.

Cover by Ted Hanke.

ACE DOUBLE: SPACE CAPTAIN / THE MAD METROPOLIS

Ace books, 1966. Cover by Gray Morrow.

Cover by Jack Gaughan.

ACE DOUBLE: BOW DOWN TO NUL / THE DARK DESTROYERS

Ace Books, 1960. Cover by Ed Emshwiller.

Cover by Ed Valigursky.

ACE DOUBLE: COLLISION COURSE / THE NEMESIS FROM TERRA

Ace books, 1961. Cover by Ed Valigursky.

Cover by Ed Emshwiller.