On July 4, 1947, in a United States with a governmental regime that appears considerably more authoritarian than the one recorded in history, a political radical named Timothy O'Mara attempts to assassinate General Norton. He fails and is summarily executed by the general. He then finds himself back in the early 1920's, inhabiting the body of a man named Tommy Bloome, whom he once murdered in order to take over his identity.
Used availability for Gordon Eklund's All Times Possible
June 1974 : USA Mass Market Paperback