entry level cryptography books

[MIKE SHAW]

Can anyone recommend some entry level cryptography books?  I'm looking for something 
that will just start to get into the nitty-gritty of the math involved.

Thanks
-Mike

[Canonical answers:
 Schneier, "Applied Cryptography"
 Menezes & Oorschot, "Handbook of Applied Cryptography".
 If anyone can say anything *new* on the subject, I'll let the message
 through.
                --Perry]