A library is a room cities use to store books and function as a form of natural Signamancy. They automatically pop (or repop) when the city is constructed or upgraded. They provide bonuses to a caster's spellcasting and experience gain.
All libraries automatically contain the 3 books of Scripture. They also contain books detailing past battles and a random selection of every book ever published. Books containing the entire history of a side will be automatically published if the side falls. A side can also publish books on its own with a Signamancer at great cost in schmuckers. Any unit capable of speaking and writing Language can write a book on any subject and have it published, though few Warlords and Rulers choose to do so. Rulers may write vainglorious treatises in self-praise, or bestiaries cataloguing all the units and ferals known to a Side and their points.WB2014 Lord Crush - Part 2