From the back cover:
The Channeling Companion explores the magic of the gods in detail. In this book, you will find new professions, variant rules, new options, and (of course) lots of stuff for priests.
Here is what you will find inside...
Four new professions that use the realm of Channeling: the Priest, the Summoner, the Warlock, and the Mythic.
A dozen new training packages for characters to develop.
Guidelines on divine status and what effect it can have in a character's life.
Rules for how to handle divine intervention.
A complete system for creating customized priests (built to reflect the details of a given religion).
Dozens of new spell lists for the realm of Channeling.
New critical tables for holy weapons and holy spell effects.