The Golden Ratio: The Story of Phi, the World’s Most Astonishing Number by Mario Livio
This is a good book referred to me by Michelle Forrest. Yearning to know more about the number “Phi” (an irrational number that is roughly 1.618) I picked up the book. Being a math guy, I appreciated the history of how Phi formed and why it is such an incredible number.
Though this book is not as good as Fermat’s Enigma and definitely not as good as Against the Gods by Peter Bernstein (see reviews at http://www.summation.net/reading.html) … so read those books first … it is entertaing as it goes over why phi is so important — but also explains why people overinflate the value of phi. Worth reading.