From publisher blurb:
Each book in the Echelon Reference Series is written to be a complete reference for a single topic.
This book focuses on the cleric class, the chosen champions and heralds of the gods.
They are a flexible class, with good core abilities and options that let them take on many roles.
In this book you will find 1 class, 11 archetypes, 48 class features, 170 class subfeatures (including 34 domains, 72 subdomains, and some variant channeling options for various divine portfolios), and 21 feats, all accessible or directly related to the cleric class. Also, 29 stat blocks for a mix of NPCs of levels 1-20, and monsters with levels in the cleric class.
This book contains material from only the PRD.