Computer Security Basics
Describes complicated concepts like trusted systems, encryption, and mandatory access control in simple terms.
Practical UNIX & Internet Security, 3rd editio
Focusing on the four most popular Unix variants today--Solaris, Mac OS X, Linux, and FreeBSD. Includes table of contents, errata, and sample chapter
Unix System Security Tools
By Seth T. Ross, from McGraw-Hill. Excerpt from the book that includes an introduction to UNIX, an introduction to computer security, a discussion of open-source security software, ten general security rules, and a bibliography.