Douglas R. Hofstadter: Godel, Escher, Bach : An Eternal Golden Braid (Paperback - Anniv. Ed.); 1999 Edition

I'm impressed by the number of reviews that say, in essence "I'm really smart, but I didn't understand it." If one is "really smart", GEB is not impenetrable, but it's not something you "understand" on the first run-through, either. Dense, yes. But repeated readings gradually release more and more of the meaning. I bought this book in 1980, and the first read got me half way through before the wheels came off. The second time I bogged down ⅔ of the way in, leaving with a little more clarity. It finally clicked on the third reading. This isn't a book you read so you can tick the check box on your master Life List; as you continually revisit it, it nudges you toward new insights, and fresh levels of confusion. If self awareness and self reference were easily accessible, there would be no need for this book. It's one of the four most important books I've ever owned.