Bluebeard by Kurt Vonnegut
Vonnegut sure knows how to deliver a gut punch in a small amount of words. The horror of war is a theme in many of his books and it is here as well. Vonnegut is a master of repeating themes, ideas, and links between characters and building up a novel to a conclusion that is inevitable, but still takes your breath away. I love his use of irony and humour as well, and just when you are getting comfortable and having a good time he drops an anvil on you.
This is a quote from Hemingway, but whenever I read Vonnegut I think of this.
All you have to do is write one true sentence. Write the truest sentence that you know.
Vonnegut writes the truest things he knows, and he does it really really well.