One of my plans as a background for a character is a librarian / bookseller-turned-adventurer, inspired by the tales of adventure in the books he has surrounded himself with. I think it's sort of sweet. It'll be difficult to realise if there are no bookshops or libraries though, hahaha.
I love the idea of player-authored books, and especially of players receiving royalties from the books they have written - an adventurer could spend his/her life exploring dungeons and ruins, discovering the world, and then make a mint after they retire from players buying their book who want to follow their footsteps.
In-game game guides written not by the developers, but by people who have experienced it first hand!