An American soldier is sent as an advisor to Egypt just after one of the Arab-Israeli wars, and he suffers hallucinatory episodes before landing of reliving a life as a soldier serving Egypt in the time when the two lands of Egypt joined. He protects the pharaoh's young son on a trip into north Africa against palace treachery and other dangers. He returns to find his betrothed had died months before by snake bite. The American and an Egyptian girl, who's his reincarnated fiancée, die in the end.
I read the book around the early 1980's.