Most needed books are kept in the quest items tab. 99% of the books are not required for game completion, they offer back story, lore or pure entertainment such as the troll survival guide you can find in the tavern. Some books hint as to what happened to some of the races since Divine Divinity. (Originally called Divinity: Sword of Lies)

Every time there I run into trouble on the road, there is always a dwarf at the bottom of it. Don't they know how to drive above ground?