sendmail includes the following sections:
Some Basics is especially useful for people new to the program. It covers the basic concepts underlying mail delivery and the roles sendmail plays in that delivery
Administration covers all aspects of handling sendmail, from downloading and installing new releases to managing mailing lists and aliases
Configuration Reference contains a heavily cross-referenced guide for configuring and tuning sendmail. Every arcane detail of sendmail is listed alphabetically
Appendices contain more detail about sendmail than you may ever need

This edition also includes new material on SSL and AUTH and a new chapter on Mitlers. If you're interested in what has changed since the last edition, one appendix categorizes the many improvements of sendmail's intervening versions by chapter, complete with references to the appropriate sections and page numbers in the book.

With sendmail, system administrators, programmers, network engineers, and even inexperienced users will be able to match this challenging but necessary utility to the needs of their network.