Besides introducing the characters, and the universe itself (approx 80 pgs.), The book contains ALL of the game. This is an ultimate walkthrough.
Not really useful because the game is not very difficult, but can serve secour wheel.
Very useful: the bestiary with the characteristics, points, etc., and the merchant list, places ...
I do not regret my purchase, it is a very beautiful object!
Far from being essential, but very pleasant.