Breakfast of Champions by Kurt Vonnegut Jr.
I was recommended this book in high school by a friend when I was going through a difficult time. It now sounds an odd recommendation, but at the time it was exactly what I needed. The book captured me instantly and I read it through in one sitting. Then the next night I read it again, and so on. I have probably read that book upwards of 20 times and each time it means something new to me. It is absolutely hilarious while at the same time it tells a story of who people are, why they act they way they do, and why people exist at all. It is about coincidence, accidents, irrelevance, nonsense, purpose and it is the perfect American Story.