Applied Cryptography  
   Bruce Schneier. A comprehensive tutorial and reference but a little light on mathematical theory.
   http://www.counterpane.com/applied.html

Handbook of Applied Cryptography  
   The online version of the 1996 CRC book by Menezes, van Oorschot and Vanstone.
   http://www.cacr.math.uwaterloo.ca/hac

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.
   http://www.math.ucalgary.ca/~ramollin/cryptopref.html

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.
   http://uk.cambridge.org/mathematics/catalogue/0521791723/

Cryptography for Visual Basic  
   Richard Bondi. Subtitled "A Programmer's Guide to the Microsoft CryptoAPI" which describes what the book is about.
   http://www.cryptovb.com/books/bondi/bondi.html

Decrypted Secrets  
   Friedrich L. Bauer. Subtitled "Methods and Maxims of Cryptology". Covers both cryptography and cryptanalysis.
   http://www.springer-ny.com/detail.tpl?isbn=3540426744

Codes and Ciphers  
   Robert Churchhouse. Describes and analyses systems from the earliest to the most recent.
   http://uk.cambridge.org/mathematics/catalogue/052181054X/default.htm

Algebraic Aspects of Cryptography  
   Neal Koblitz. A textbook for a course, or self-instruction, in cryptography with emphasis on algebraic methods.
   http://www.springer-ny.com/detail.tpl?isbn=3540634460

Coding Theory and Cryptography  
   David Joyner, editor. Proceedings of the 'Conference on Coding Theory, Cryptography, and Number Theory' held at the U.S. Naval Academy during October 25-26, 1998
   http://www.springer-ny.com/detail.tpl?isbn=3540663363

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.
   http://www.osborne.com/networking_comm/007213139X/007213139X.shtml

The Twofish Encryption Algorithm  
   Schneier, et al. Covers design, performance, instructions and source code in C.
   http://www.wiley.com/cda/product/0,,0471353817,00.html

Cryptography and E-Commerce  
   Jon C. Graff. Geared to nontechnical managers who want to explore the underlying concepts of this topic.
   http://www.wiley.com/cda/product/0,,0471405744,00.html

Primality and Cryptography  
   Evangelos Kranakis. A comprehensive account of recent algorithms developed in computational number theory and primality testing.
   http://www.wiley.com/cda/product/0,,0471909343,00.html

Contemporary Cryptology  
   Gustavus J. Simmons. Subtitled "The Science of Information Integrity". Has emphasis on the cryptographic elements of the subject.
   http://www.wiley.com/cda/product/0,,0780353528,00.html

Elementary Cryptanalysis  
   Abraham Sinkov. An older book (1966) that covers the mathematical side of elementary cryptography. Published by 'The Mathematical Association of America'.
   http://www.maa.org/pubs/books/nml22.html

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.
   http://www.dcc.ufrj.br/~collier/rsabook.htm

A Course in Number Theory and Cryptography  
   Neal Koblitz. An algorithmic approach that covers basic arithmetic topics all the way to elliptic curves.
   http://www.springer-ny.com/detail.tpl?isbn=0387942939

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.
   http://www.cacr.math.uwaterloo.ca/~dstinson/CTAP.html

Security Engineering  
   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.
   http://www.cl.cam.ac.uk/~rja14/book.html

In Code  
   Sarah Flannery's supplement to her book "In Code", describing her Cayley-Purser algorithm.
   http://cryptome.org/flannery-cp.htm

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.
   http://www.youdzone.com/cryptobooks.html

The Code Book  
   Simon Singh. Traces the development of codes and code-breaking from military espionage in ancient Greece to modern computer ciphers.
   http://www.simonsingh.net/The_Code_Book.html

The Interactive Cryptography Tutorial  
   Online tutorial with useful info and links.
   http://www.antilles.k12.vi.us/math/cryptotut/home.htm