Godel,Escher,Bach an Eternal Golden Braid
Author: Douglas R. Hofstadter
730 pages (Long but written in a way that anybody could understand it.)
The book talks in great detail about many of the concepts on this site. One thing it does a very good job of is explaining how something as complex as the mind can come from a bunch of neurons. It also has many chapters on AI and gives you a good lesson on basic number theory and formal systems. At the end of each chapter there is a fiction portion which gives you a good example of the ideas being discussed. When buying books I suggest using ebay or amazon.com. I got my copy of GEB for $8 on amazon.