The Codebreakers: The Comprehensive History of Secret Communication[0] by David Kahn is probably the best book in this area. Be warned it sits on many bookshelves but due to its length few are the number that have finished it, none the less it is an extremely rewarding read. It has oddles and oddles of stories about cryptographers you have never heard of doing awesome things, including the history and personalities behind many of the Black Chambers of Europe.

It puts the Code Book to shame.

[0]: http://www.amazon.com/The-Codebreakers-Comprehensive-Communi...