Cosmic Trigger: Volume I is a very interesting and strange book by Robert Anton Wilson that is part nonfiction and part completely far-out weird. Much of the nonfiction parts of the book are an autobiographical sort of tale about RAW's life in the 60s and 70s, along with the people he associated with like Timothy Leary.
The book is filled with strange conspiracy theories, science fiction theories of aliens and the universe, and lots of insight on life and all the grand things that happen in the world. I love RAW's writing style and agnostic sense of humor and really enjoying reading this book. It can be a bit too strange or difficult to understand at times but if the reader puts the effort into it and doesn't take the book all too serious than it's really wonderful.
I would recommend that people pick up The Illuminatus! Trilogy first if they haven't read any of RAW's work, although this book is short enough to give the prospective reader a glimpse into the mind of a very strange man.