Listmania!
Favourite Cryptography Books
Handbook of Applied Cryptography (Discrete Mathematics and Its Applications)Handbook of Applied Cryptography (Discrete Mathematics and Its Applications) by Alfred J. Menezes
Buy new: £33.74 / Used from: £24.99
Excellent reference, but I wouldn't start with this one
Cryptography Theory and Practice (Discrete Mathematics and Its Applications)Cryptography Theory and Practice (Discrete Mathematics and Its Applications) by Douglas R. Stinson
Buy new: £37.68 / Used from: £36.90
Perhaps the best textbook
Applied Cryptography: Protocols, Algorithms and Source Code in CApplied Cryptography: Protocols, Algorithms and Source Code in C by Bruce Schneier
Buy new: £24.67 / Used from: £17.00
Great collection what crypto can do; gives a nice overview
A Course in Number Theory and Cryptography (Graduate Texts in Mathematics)A Course in Number Theory and Cryptography (Graduate Texts in Mathematics) by Neal Koblitz
Buy new: £37.09 / Used from: £13.68
The math of crypto
Practical CryptographyPractical Cryptography by Niels Ferguson
Buy new: £18.89 / Used from: £12.00
Nice followup to Applied Cryptography
The Code Book: The Secret History of Codes and Code-breakingThe Code Book: The Secret History of Codes and Code-breaking by Simon Singh
Buy new: £5.97 / Used from: £2.50
Good, entertaining history