Without requiring administrators to understand the complexities that are characteristic of Sendmail, Postfix offers electronic mail services reliably and with sufficient configurability. Sections on the messages back and forth during Post Office Protocol (POP) and Simple Mail Transfer Protocol (SMTP) sessions are informative, and a list of configuration files clarify what you should do to get the function you want. Some administrators may find some parts that were written at the level too basic for someone installing Postfix, but at the end of the day, most readers will agree that it's better to assume too little in a technical book than to assume too much. Especially interesting part has to do with migration from Sendmail to Postfix, integrating OpenLDAP with Postfix, and tying Postfix to databases.