Crossover Cover: The Tides of Kregen

This series of novels features Dray Prescot, an Earthman who has been transported several times to the planet Kregen by alien super beings known as the Star Lords. While there, he has had many swashbuckling adventures and married a princess. In this novel, after rebelling against the Star Lords’ dictates, he is sent back to Earth for twenty years as punishment. He spends time in America fighting for the Union in the Civil War. At the end of the war, he meets a man from Virginia who he believes would like a life like his. This man is clearly meant to be John Carter. Kregen may be in the same alternate universe as the Mars/Barsoom to which Carter was transported.