New York: Harcourt, Brace and World, 1967. Hardcover with dustjacket. Third printing.

Picture from bfell@nni.com.

ACE single 63410.

Picture and information from ACE covers library .

Fawcett Crest edition from 1981.

Picture and information from Kathryn Staley .

An Ace book cover for Operation Time Search $0.95 -it seems to be second printing august 1973 coverart by Jack Gaughan.

Picture and information from Jens-Chr. Kjaer .