Slaughterhouse Five is Vonnegut's most famous novel and the book which launched him into the discussion as America's greatest living writer, made him all the money he would ever need and, possibly, caused him to go insane for most of the 1970's.

It's an almost autobiographical book about a man, Billy Pilgrim, who becomes unstuck in time - which means he experiences all of the events of his life out of order and repeatedly. He knows everything that has and will happen to him simultaneously - including an alien abduction (conveniently by aliens who regularly experience all of time simultaneously).

The focus of the book is on Pilgrim's status as a prisoner of war at the end of WWII and his being among the very few survivors of the Allied fire bombing of Dresden (the single greatest lost of life in one day in the history of warfare) - an event which Vonnegut really lived through.

Vonnegut narrates the book, but also includes himself as a minor character - using the first and last chapters to explain his role in the story and set up the narration. Clearly this was an element of catharsis for Vonnegut as he dealt with his understanding of life and death.

It's so rich in imagery and philosophy as well as the typical Vonnegut call backs to previous writing. His full irreverence is finally allowed to be published (written in 1968, the publishing industry and culture in general become quite less prudish).

The writing and story are truly masterful, and while the narration does not wrap up as neatly as Cat's Cradle, clearly this is an important novel - certainly among the five most important novels written in the US.