Cryptography book reviews, links to online erratas, and free book downloads. Most books have charts that recommend prerequisite books, mathematics and programming language experience.
Douglas Stinson. Subtitled "Discrete Mathematics and Its Applications". Written with more emphasis on theory than practice, as acknowledged in the preface.
Richard A. Mollin. Intended for a one-semester introductory undergraduate course in cryptography. Covers symmetric and public key systems with chapters on advanced topics.
Anderson, Ross. Author describes book in his own words. He explains how "pure" cryptography is not quite so pure when expressed in the context of real world applications.