Ace Books published 221 science fiction Ace doubles between 1952 and 1973 in tête-bêche format, and a further 40 between 1974 and 1978 in a more traditional format in which the two books are both the same way up.
Ace Books published 221 science fiction Ace doubles between 1952 and 1973 in tête-bêche format, and a further 40 between 1974 and 1978 in a more traditional format in which the two books are both the same way up. (en)