Warning: Wikipedia contains spoilers.
It is perhaps Vonnegut's most popular work and is regarded as a classic work. It is unusual in the way it combines science-fiction with analysis of the human condition, and most especially the bombing of Dresden.
When the book was released the Dresden bombing was not widely known and was little spoken of by veterans or historians. The book helped to increase world awareness of the massacre and led to a reevaluation of the attack's justification.
American soldier Billy Pilgrim is captured by German soldiers and is forced to live in a makeshift prison. Pilgrim is "unstuck in time" and randomly visits different parts of his life. He is also taken by aliens from the planet Tralfamador who see in four dimensions, the fourth dimension being time, which allows them to examine any moment in time that they wish. While on Tralfamadore, Billy is exhibited in a zoo, naked with a movie star from earth, Montana Wildhack. The book examines many events in Billy's life including his death, and the infamous bombing of Dresden, the inspiration of the book which the author, Kurt Vonnegut, himself experienced.