Gateway by Frederick Pohl. Great book.
It is a kind of dialogue between main character an AI (artificial inteligence) psychoanalyst woven with his personal history. Main character feels guilty that killed women he loved, that he is incompetent. His psyche is a real swamp, he doesnt even want to admit his faults. He fights with AI to keep his secrets, his privacy. He could resign this therapy but he needs that fights, he cant live without it. AI knows all his records and test his reactions. Ask him about his memories, mostly about that one which hurts, really hurts.
And paralelly we get to know his story and story of his world - first class SF!!!!!. Humankind found artifacts of another sentient race. Race which could travel between stars. Race which has visited our planet about a quater of million years ago. Some of these artifacts were space-ships. Nobody knows how these ships worked but some of them still work...

Read it!