From the back cover:
"Hammers of Faith contains everything you need to know about the armies of the North, including:

- An overview of Northern politics and history

- Backgrounds on all the major war machines

- In-depth Field Guides for the Northern Guard and all three Northern league armies

- New squads and options to let a Northern commander handle nearly any situation

- 30+ Datacards, covering all Northern designs and major variants, for easy reference

Supplement for Heavy Gear Blitz! requires the main Heavy Gear Blitz! Rulebook (DP9-996) to play."