Quantum Computing Since Democritus by Scott Aaronson. A brilliant MIT professor's reflections on the intersection between computer science, physics and philosophy. Here are the lecture notes and book: http://www.scottaaronson.com/democritus/ I also very much recommend the author's blog: http://www.scottaaronson.com/blog/
Similarly to books like GEB, it really exposed me to a whole range of fascinating ideas and topics that I am now interested in.