Critics of Kurt Vonnegut's are unable to agree on what the main theme of his novel Slaughterhouse Five may be. Although Vonnegut's novels are satirical, ironical, and extremely wise, they have almost no plot structure, so it is hard to find a constant theme. From the many people that the main character Billy Pilgrim meets, and the places that he takes us, readers are able to discern that Vonnegut is trying to send the message that there will always be death, there will always be war, and humans have no control over their own lives.
Most of the book is the narrative from Billy Pilgrim a unique character who has the ability to become "unstuck in time", which means that he can uncontrollably drift from one part of his life to another "and the trips aren't nessicarilly fun". The whole books is organized in the same way Billy moves in time. In consists of numerous sections and paragraphs strung together in no chronological order, seemingly at random. The whole narration is written in the past tense, so that the reader cannot identify where the author's starting point is. This aspect of the book is almost identical with the Tralfamadorian type of book:
"There isn't any particular relationship between all the messages, except that the author has chosen them carefully, so that,when seen all at once, they produce an image of life that is beautiful and suprising and deep. There is no beginning, no middle, no end, no suspense, no moral, no causes, no effects. What we love in our books are the depths of many marvelous moments seen all at one time."
I agree with Mark Vit when he says that the most often expressed theme of the book is that we, as people, are "bugs in amber". The phrase first appears when Billy is kidnapped by the Tralfamacorian flying saucer:
"Welcome aboard, Mr. Pilgrim." said the loudspeaker. 'Any questions,?'
Billy licked his lips, thought a while, inquired at least: 'Why me?'
That is a very Earth...