Wow.  I picked up “The Golden Ratio” when I went shopping for Quicksilver the other day, and actually started reading it before Quicksilver.  No regrets so far.  It's not so much a math dissertation as it is a study of the impact on society this little bugger's had - the Pyramids, violins, and the smile of the Mona Lisa, among others...  This is a great read - highly recommended.