A library is a room in a dungeon based upon a design taken from a Dungeon Heart. It stores the magical knowledge of the Keeper and makes it more accessible for the Keeper as well as its minions. Sensible data, such as details for the creation of dungeon hearts, is edited out.
The data is stored in tomes and books. Furthermore the library doubles as a laboratory if there is not a special room set aside for research. This laboratory includes beakers and further alchemical equipment, and at least one Crystal Ball.