The Time Traders by Andre Norton, 6th printing, Ace, 1984.
Born Alice Mary Norton in Cleveland, Ohio, she chose Andre Norton as a pen-name at a time when genre fiction was expected to be written by male authors, and changed her name legally in 1934. Andre, she felt, was ambiguous enough to allow her to write for teenage boys, and many were surprised to find that "Mr Norton" turned out to be a slender, brown-haired and green-eyed young woman.
Norton's novels feature adolescent, independent, often alienated heroes and heroines struggling with their own individuality as they discover more about themselves and the world they live in. These rites of passage are played out against fast-moving quests, with enough action to enthral a teenage audience. (the guardian)
"This exciting story is set in the last quarter of this century, but the action takes place in several levels of time and periods of history and prehistory. A young convicted criminal becomes a volunteer in a government program which trains men to do research in these various eras. Object: the discovery of scientific secrets lost before the dawn of history. The hero is pictured as a kind of commando personality, a nonconformist in civilized society but the ideal man in primitive times." (Saturday review, 1958)
-no markings inside
-very good condition