Slaughter House Five by Kurt Vonnegut

Chaplain's Assistant Billy Pilgrim, a disoriented, ill-trained American soldier, is captured by the Germans in the Battle of the Bulge. The Germans imprison him and other PoWs in a disused slaughterhouse in Dresden. During Allied air raids, PoWs and guards alike hide in a deep cellar; because of their safe hiding place, they are some of the few survivors of the city-destroying firestorm.

For unexplained reasons, Billy has come "unstuck in time." He is kidnapped by extraterrestrial aliens from the planet Tralfamadore. They exhibit him in a zoo with movie star Montana Wildhack as his mate. The Tralfamadorians, who can see in four dimensions, have already seen every instant of their lives. They believe they cannot choose to change anything about their fates, but can choose to concentrate upon any moment in their lives, and Billy becomes convinced of the correctness of their theories.

Billy travels forward and back in time, reliving occasions of his life, real and fantastic. He spends time on Tralfamadore; in Dresden; in the War, walking in deep snow before his German capture; in his post-war married life in the U.S.A. of the 1950s; and in the moment of his murder.

Billy's death is the consequence of a string of events. Before the Germans capture Billy, he meets Roland Weary, a jingoist character who constantly chastizes him for his lack of enthusiasm toward war. At their capture, the Germans confiscate everything Weary has, including his boots, giving him clogs to wear; Weary eventually dies of gangrene caused by the clogs. In his deathbed, Weary managed to convince Paul Lazzaro that Billy is to blame for; Paul vows to avenge Weary's death by killing Billy, because revenge is "the sweetest thing in life". Time-traveler Billy, already knows where, when, and how he will be killed: Paul Lazzaro hires someone to shoot him after a speech in a balkanized United States on February 13, 1976.