As it stands now, to the best of my knowledge, to perform certain actions, such as smelting iron ore for example, you need to "have on your mind" a particular book. So, if your into knowledge and want to learn lots of things, you're forced to lug around various books, at least until they implement player housing or some way to store items you don't want to pack around all the time. What if, once you attain a particular book, and start using it with some regularity, after a certain amount of time/uses, because of sheer repetition you no longer need to have it "on your mind" to perform the task because you now know it by heart. Makes sense to me. I suppose you could also tied it in with trained levels instead, once you have reached a certain level of proficiency you wouldn't need the book anymore. You could also make it so that if you don't use a skill for some time, it may deteriorate a little and you might have to use the book again (probably for less time than when you first started because it would be more of a refresher).
