A full decent implementation of this sort of thing would probably require a development arc unto itself:
You'd need to have the ability to make paper(1), books(2), and inks(3). Then you'd have to get the dwarves to actually write in the books(4), new furniture to store the books(5).
Beyond just the dwarves, you'd have to figure out how books and the assorted paraphernalia would work for the other civs in the world. What form do books take for humans, for elves, for goblins and kobolds? What information might be stored in them? Book detailing each civilization's historical events might be one. Marriage and birth records in one book, wars in another, deaths in a third. If a civ is inclined towards writing fiction, how would what is written change from civ to civ?
You'd have to add in considerations in adventure mode as well. Finding the lair of that Cyclops the mayor just told you to kill might require your adventurer to spend some time in the town library reading through various books and tomes until it's location is discovered. You might not be able to rely on just talking to townsfolk to find out where everything is.
I'm sure there's plenty of other stuff which could pad out this idea. I'd love to see this sort of thing implemented! But it would just be icing, really.
Expanded-upon ideas from above:
(1) Papermaker shop. Possibly similar to how a loom works, with the added benefit of being able to use all those old clothes in the creation of rag papers. Other materials could be considered and new paper producing plants might be introduced to fill new roles.
(2) Bookbinder workshop. Would require new jobs to be implemented.
(3) Maybe work it into the Alchemist's workshop, or at the Dyer workshop. If/when magic is introduced, maybe only magical inks could be used in the scribing of spellbooks?
(4) New job: Scribe and others. Maybe there's only one official scribe in any given fortress, as it might be a noble position. The Philosopher might start making book writing demands, or start scribing books of their own.
(5) Preferably with the ability to designate a room with a library specific function. What that would be or do, I have no idea; research perhaps.
