It contains conversion material for the core rules as well as selected supplemental rules, and is actually longer than the original book by sixteen pages, or one signature. It also includes information about the Grigori and their resonance, as well as the Fallen Grigori (also known as Skulkers), which has not yet appeared in the original line. The conversion guidelines in the back can convert both to and from GURPS and the original system.
The character point values for Celestial characters in GURPS In Nomine are very high in relation to most other GURPS settings. Starting characters can easily exceed 800 points, and more experienced characters are likely to exceed 1500 points.