An Introduction to Cryptography: Richard A. Mollin. Intended for a one-semester introductory undergraduate course in cryptography. Covers symmetric and public key systems with chapters on advanced topics.
Applied Cryptography: Bruce Schneier. A comprehensive tutorial and reference but a little light on mathematical theory.
Codes and Ciphers: Robert Churchhouse. Describes and analyses systems from the earliest to the most recent.
Contemporary Cryptology: Gustavus J. Simmons. Subtitled "The Science of Information Integrity". Has emphasis on the cryptographic elements of the subject.
Cryptography and E-Commerce: Jon C. Graff. Geared to nontechnical managers who want to explore the underlying concepts of this topic.
Cryptography book recommendations: Cryptography book reviews, links to online erratas, and free book downloads. Most books have charts that recommend prerequisite books, mathematics and programming language experience.
Cryptography Decrypted: Mel and Baker, has sample chapters.
Cryptography for Visual Basic: Richard Bondi. Subtitled "A Programmer's Guide to the Microsoft CryptoAPI" which describes what the book is about.
Cryptography Theory and Practice: Douglas Stinson. Subtitled "Discrete Mathematics and Its Applications". Written with more emphasis on theory than practice, as acknowledged in the preface.
Foundations of Cryptography: Oded Goldreich. Focuses on the basic mathematical tools needed for cryptographic design: computational difficulty (one-way functions), pseudorandomness and zero-knowledge proofs.
Handbook of Applied Cryptography: The online version of the 1996 CRC book by Menezes, van Oorschot and Vanstone (5th edition) in PostScript and PDF formats.
In Code: Sarah Flannery's supplement to her book "In Code", describing her Cayley-Purser algorithm.
Primality and Cryptography: Evangelos Kranakis. A comprehensive account of recent algorithms developed in computational number theory and primality testing.
RSA Security's Official Guide to Cryptography: Burnett and Paine. Explains the differences between symmetric-key and public-key cryptography, how PKI and X.509 affect security and how the RSA algorithm works within protocols.
Security Engineering: 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.
The Code Book: Simon Singh. Traces the development of codes and code-breaking from military espionage in ancient Greece to modern computer ciphers.
The Interactive Cryptography Tutorial: Online tutorial with useful info and links.
The Mathematics of Ciphers: S.C. Coutinho. An introduction to number theory and its applications to cryptography. A revised and updated translation from original in Portuguese.
The Twofish Encryption Algorithm: Schneier, et al. Covers design, performance, instructions and source code in C.