Frank W. Putnam (1) (1947–)

I had this book on my reading list when I was studying for quals. I meant to read only a little section of it, because I was really busy and had a ton of stuff to read in a very short time. However, the book is so fascinating and so well-written that I kept reading whole chapters while I was looking for other information... eventually I gave up and read it almost cover-to-cover in one sitting. Highly recommended.