I have what is either a very bad habit or a very good habit. Whenever I come across a reference to a book on a subject I know very little about, I put everything else I want to read aside and read that book instead. In this case, the subject was cryptography, and the book is Simon Singh's The Code Book. Covering the history of codemaking and codebreaking from ancient civilizations, through the development of mechanical enciphering (esp. the Enigma machine and Bletchley Park) and up to public key encryption and the possibilities implied by quantum computing. All of this, with a brief detour into the deciphering of Hieroglyphics and Linear B, is explained in terms that a layman (i.e. me) can understand.
One reason I hesitate to review books like this is my knowledge on the subject is so scarce that I can't really speak to its veracity. Unlike some non-fiction books (*cough* Freakonomics *cough*), there are no obvious problems that stick out. This is not a bad thing, but could indicate a very good book or a book that seems very good to someone who doesn't know what they're talking about (i.e. me). Anyway, assuming Singh's work is as well-researched and accurate as it appears to me, it's a good primer on a subject that will only become more relevant to the average person as time passes.