My favorite is "Apollo: Expeditions to the moon" which was released by NASA at the end of the Apollo program.
http://www.amazon.com/Apollo-Expedit.../dp/9997398270
or NASA has a (pretty dodgy) digital copy online at:
http://history.nasa.gov/SP-350/cover.html
Pretty technical and each chapter is written by the key people responsible, for example the Apollo 11 section is written by Aldrin and Collins and the Saturn V chapter is written by Von Braun!
I would also recommend "Moonfire" by Norman Mailer if you like his writing and that book has lots of great images.