Site Security Planning

Extranets by Richard H. Baker, 1997, New York: McGraw-Hill.: A complete sourcebook on how to plan, implement and secure extensions to your intranet that reach out to business partners and customers.
Mastering Internet Security by Chris Benton, 1998, Cybex.: The book is a comprehensive guide to planning security, writing security policies, as well as choosing and using security tools for a multiplatform network.
Hacker Proof, The Ultimate Guide to Network Security by Lars Klander, 1997, Houston: Jamsa Press.: A great resource for understanding network security issues and learning what to do about them. Excellent descriptions of encryption and hash values.