Ace SF Doubles

First published in hardback by Gnome Press in 1950. This paperback edition published by Ace (D-36) as part of an SF Double is dated 1953. Cover art by Norman Saunders.

Published by Ace (D-26) as part of an SF Double in 1953. Cover art by Robert E. Schulz.

Originally serialized in "New Worlds" in 1958" as "Equator." This first paperback edition published by Ace (D-369) as part of an SF Double in 1959. Cover art is not credited, but the signature of Ed Emshwiller can be seen below the man's left hand.

Published by Ace (D-369) in 1959 as part of an SF Double. Cover art is uncredited, though the Ace Image Library credits Ed Valigursky.

Published by Ace (F-104) in 1961 as part of an SF Double. Cover art by Ed Emshwiller.

Published byAce (F-265) in 1964 as part of an SF Double. Cover art by Jack Gaughan.

Published byAce (F-265) in 1964 as part of an SF Double. Cover art by Jack Gaughan.

Published by Ace Books (M-107) as part of an SF Double in 1964. Cover art, though not credited, is by Ed Valigursky. An ocean liner adrift in deep space makes a memorable image.

Published by Ace (M-111) as part of an SF Double in 1965. Uncredited cover art by Jerome Podwil.