This book has 14 chapters:
1: history of Westeros
2: Westeros culture
3-12: This is the bulk of the book, each chapter represents a large area of westeros (The stormlands, the North, etc.), describing each area in great detail. It details the major house of the area, other major houses, minor houses, the geography, and the history. It also includes bios on all important characters including their stats
13: Beyond Westoros
14: Exploring Westoros
As mentioned, this book details westeros very well, but once you get to the stats of individual characters the quality becomes very poor. For example, even though the rulebook very clearly defines the status of a number of characters, the campaign guide seems to arbitrarily assign status (Sam Tarly and Tyrion have equal status). Just about anything in this book related to the mechanics of the RPG is inconsistent with the rule book, which will make playing the game on the fly frustrating.
As I said, the detail of Westoros is wonderful, but you could get the same detail for free from the online wiki. My suggestion is to not purchase this item for the specific purpose of supplementing your SIFRPG games.