pfSense: The Definitive Guide
The Definitive Guide to the pfSense Open Source Firewall and Router Distribution
by Christopher M. Buechler and Jim Pingle
The following images are of a draft copy of the book from August 2009. This cover is designed by Holger Bauer. The photos here don't give it justice -- there is a faint red line at the top and it has a ".org" after the "pfsense".