The field of cryptography and related disciplines has moved very quickly in recent years as the explosion of computing power and the growth of electronic commerce have made terms like "public key encryption" and "pretty good privacy" familiar to more than the cognoscenti. Singh has done an excellent (and blessedly concise) job of retelling the history of code writing to the present day. A skilled journalist and television producer, he should be particularly commended for the book's graphics, which help explain ideas otherwise too abstruse for the lay reader. A well-chosen bibliography (including Web sites) rounds out an excellent introduction to the subject.
