+1 for the library.
That would be much better than Skyrim's ten books repeated and then a few skills books scattered throughout the world, also better than DAOs book-badge-hunting.
Also, +1 for reading letters, books and what not when you click on them in situ, that's a lovely feature in DD, just make sure that font sizes and the like are scalable and adaptable. So many CRPGs are hurting because of the lack of that as they have aged and monitors have become more highrez.
