Somewhat related, but not exactly:
I have a single generic book that is useable. It has a single description that is fairly nondescript.
Upon use of the book, my library system evaluates the reader's lore and other factors to see if you can 'read' it. If so, it adds a new description to the book, replacing the original one.
I use lots of factors to determine the book types and potential content (e.g. the location where the book is found, the rarity of the book, etc...) Once the book is selected a description is returned and replaces the default description. I also modify the image of the book to take advantage of all those cool book icons.
My point is that, rather than having a multitude of books in a library or in the loot, you could have 1 custom useable book that triggers a library system that effectively gives you an unlimited library of content. It also gives you easy control over all the lore contained in your books since it is all stored in one place. Also, for those 'illiterate' adventurers, they'll never be able to decipher a book's contents.
Just a thought.