While Vonnegut says in the very first chapter of Slaughterhouse Five that he intends the story to be an “anti-war book” (which he admits will be about as pointless as an “anti-glacier book”), it seems to me that he also (and probably not secondarily) intends it to be a platform for questioning some basic tenets of Christianity.
The main character is Billy Pilgrim, whose name is significant in that he's a childlike American who finds himself on a sort of a spiritual journey. Throughout the novel, the author draws parallels between biblical events and the events in the story, although these parallels aren’t always immediately evident. As Billy’s journey takes him down paths of dubious validity (specifically, abduction and captivity by friendly aliens), we eventually see what Vonnegut is saying: Billy’s complete faith in his extraterrestrial experiences is similar to, and as silly as, the believers’ faith in Christ.
Sooo, fair warning: If you’re a Christian who doesn’t like to be questioned or challenged, you’ll probably find Slaughterhouse Five an uncomfortable read. But if you’re up for some challenging thinking outside the Bible box, you’ll find lots of thought-fodder here.
As for the story itself, it is not driven by a linear plot. In fact, as Billy hops involuntarily and unpredictably back and forth through time, the story develops like a puzzle, with each vignette adding a new piece of the intended picture. You see more clearly what the author wants to say as the puzzle gets closer and closer to completion. Instead of being swept into the story by a riveting plot, you’re carried by your empathy for Billy and by intrigue at the philosophical ideas Vonnegut subtly presents through him and the people he finds himself attached to.
The first and last chapters work like a picture frame. After finishing the book, you may want to reread them. Vonnegut plants several little ideas there which may have seemed inconsequential on the first reading. On second look, though, you’ll understand how significant they are, and you’ll appreciate the masterful way he develops those seeming trivialities into key elements of Billy’s story.
Since I read Slaughterhouse Five not long after finishing Unbroken (Laura Hillenbrand), I'll give ya a little “compare & contrast.” While both are WWII stories, the obvious difference is that Unbroken is a biography and Slaughterhouse Five is blatantly fiction.
Other differences:
Unbroken’s humor is light and quippy. Slaughterhouse Five’s humor is dark and sardonic.
Unbroken’s prose is conversational. Slaughterhouse Five’s prose is poetic.
Unbroken celebrates Christianity. Slaughterhouse Five seriously questions it.
Also, Unbroken and Slaughterhouse Five have entirely different objectives. Unbroken lauds an American hero by minutely detailing the horrors he suffered and his actions toward survival and success. On the other hand, the Slaughterhouse Five war stories, which are nowhere near as graphic, serve mainly as background for the characters’ psychological development. In Slaughterhouse Five, there are no overt heroes. Instead, we see mostly childlike soldiers who develop various neuroses and psychoses as a result of their war experiences. And I suppose that’s what makes it an “anti-war book.”
