Billy pilgrim is an optometrist from Ilium, New York.  He had attended one semester of night sessions at the Ilium School of Optometry before he became a soldier in the US infantry in World War II.  He was taken prisoner by the Germans, and after being moved here and there he ended up in Dresden, where he witnessed the dreadful bombing of that city, which caused a firestorm killing tens of thousands of citizens.  After the war he was the only survivor of a plane-crash, and while he was recovering in the hospital his wife died of carbon-monoxide poisoning.  A decennium later Billy was killed by someone with a high-power lasergun.

This is in a nutshell the entire story, yet it isn't as one important part is missing, and it's impossible to insert it nicely in that time-line: Billy Pilgrim frequently and totally unpredictably became unstuck in time: one second he could be in the hospital in the sixties, the next he could be in the second World War.  This is not something he can control, though he does have an explanation for it: it all started when he was abducted by little green men from the planet Tralfamadore.  They taught him that time is some kind of a dimension humans cannot fully comprehend.  According to what he learned time isn't a line, but a series of moments, and each of those moments exist forever.  And he just jumps back and forth, from one moment in war to another to his youth to the time he was displayed at Tralfamadore in something like a zoo.

Don't worry, it's a lot easier than it sounds.  It does create the odd effect that you learn about each of those moments at the same time, and almost at the same pace.  Only after reading half the book you start noticiing that the pieces start to fit together.  But as I said, it's not something that complicates things, on the contrary.

An important theme in this book is of course the needless slaughter at Dresden, where thousands of tons of explosives massacred an unimaginable number of people in just a few hours in the most horrible way.  Billy Pilgrim, like Kurt Vonnegut himself, survived this bombing by being at the right place at the right time by pure luck.  Needless to say it leaves a huge impact, one could even argue that the idea of being unstuck in time and travelling back and forth is just Pilgrim's mind trying to deal with the horrors he experienced.  Somehow I don't believe this though, that explanation is too easy.

Oh sure, the entire story is an attempt to deal with his memories and experiences, and the entire book is a cry against the madness of war.  After reading this concepts like "surgical warfare", "collateral damage" or "friendly fire" all sound a bit hollow, no matter what videogame-style reports from any war is trying to pretend.  No wonder not everyone would like too many people to read this book.