Slaughterhouse-Five.

Billy Pilgrim, a veteran of the Second World War, finds himself mysteriously detached from time, so that he is able to travel, without being able to help it, from the days of his childhood to those of his peculiar life on a distant planet called Tralfamadore, passing through his bitter experience as a prisoner of war in the German city of Dresden, over which looms the inevitable shadow of an unspeakable tragedy.