The following is a list of books about PGP. They provide in-depth information about various aspects of PGP, encryption and security.
The Official Pgp User's Guide
by Philip R. Zimmermann
MIT Press 1995
ISBN 0-262-74017-6
127 pp. $21.95
PGP: Source Code and Internals
by Philip R. Zimmermann
MIT Press 1995
ISBN 0-262-24039-4
900 pp. This is out of print
PGP: Pretty Good Privacy
by Simson Garfinkel
O'Reilly & Associates 1994
ISBN 1-56592-098-8
430 pp. $27.96
Protect Your Privacy: The PGP User's Guide
by William Stallings
Prentice Hall PTR 1995
ISBN 0-13-185596-4
302 pp. This is out of print
Applied Cryptography:Protocols, Algorithms, and Source Code in C
2nd Edition, by Bruce Schneier
Wiley Publishing 1996
ISBN 0-471-11709-9
784 pp. $43.96
The Computer Privacy Handbook:The
Computer Privacy Handbook: A Practical Guide to E-Mail
Encryption, Data Protection, and PGP Privacy Software
by Andre Bacard
Peachpit Press 1995
ISBN 1-56609-171-3
This is out of print