I inted to use this book the way I use guides, wikis and what not - to get as much background information as possible. I generally like settings where I know more than just what is presented in the game. I also like references to characters or subplots I've read about elsewhere (i.e references to Dak'kon in both BG2 and NWN2, the intertwined story and settings of the HoMM/MM universe, etc).
I probably won't be able to find this at the local bookstore though, so I'll probably have to buy it online.