I'm not too fond of having 'generic' books, though. I'd at least like to have them category specific. So, you could use any Medical book to study Diagnosis or Bone setting or whatever, but you couldn't use it to study Mining or Herbalism. Generic books just seems...odd.
Did a quick test, looks like jobs can only use/train a single skill. That's unfortunate. Looks like the Scriptorium will have a giant list of jobs that can be done at it.
I think I'll stick up a poll with the options. There are three basic options, I think.
1) Large General Library. A single, large workshop that needs 1 manuscript of each of the various subject areas to be built. The advantage is that you've got a single place to do everything, you don't need a ton of books on each subject, and I can make it look pretty snazzy. Disadvantage is that you can only have one dwarf study in there at any given time, and you can't just make a library to deal with one or two subjects.
2) Smaller Specific Libraries. Small library sections that are used for a specific subject area. Agriculture, for instance, or Medicine. They would require a few manuscripts of the appropriate type to be built. This lets you have as many or few sections as you want for a given subject and you don't have to clutter up your fortress with books. Disadvantage is that you have to make a lot of them to cover all subject areas.
3) Generic libraries and stockpiled books. Small library sections that can be used to study any book. This makes the books you have on hand the only limiting factor in their use. Disadvantage: You have to have book stockpiles sitting around, so you have an odd disconnect of having a library without any real shelves. Probably just bins of books.
I kind of like 2, since I like the fact that I can build in a selection of books to the library sections. So you'd need to have, say, five manuscripts on medicine in order to start training doctors. It doesn't truly enforce the knowledge transfer logically, since they could all be on diagnosis but somehow train surgery, but it'd be closer. It also means that each library has a somewhat limited set of actions in the menu, making it easier to navigate. But 3 has some nice aspects as well. I just that stockpiles could be made more fine grained. Right now you can't quite restrict it so that ONLY books and no other tools end up in the stockpile.