Mine is Gödel, Escher, Bach: An Eternal Golden Braid by Douglas Hofstadter.
I was given that book as a gift a few years ago by a girl who thought I was very smart. Unfortunately she overestimated my intelligence. I got maybe halfway through it. It was not light reading. I really should finish it, some day. Then I should start it from the beginning again.[/quote]
I just got it, read the intro and first chapter and it's absolutely fascinating!
What surprised me the most so far is that Babbage in the 1800s discovered meta-programming, without a proper computer to test it on. Today, if we have that particular bit of knowledge, it's because McCarthy rediscovered it in 1956 and today, not many programers can understand it. That Babbage discovered it is crazy!
By the way Stu, when are you going to read "How to Win Friends and Influence People"? :)