Wait wait wait wait what
Your dwarves actually learn skills from books?! Mine NEVER do!
I believe it's dependent on their student skill. I experimented with reading a bunch of books about medicine in adventure mode and while i never got to the point of increasing diagnosis or surgery, I noticed my student skill increase. I believe eventually my skills would get a boost from reading relevant books.
In fortress mode, discussions seem to be the better way for skills to be increased (or at least kept from rusting).
I assume it's the books, but I could be wrong. I just don't see what else would explain so many dwarves dabbling in medical skillls.
Yeah so what's the point of libraries again? Do they have any practical benefits?
Right now they are a good way of spreading medical skills among your dwarves, and the writings of your scholars provides entertainment to those who read them. Its also an alternate way of raising student and teacher skills (which still have their old use in military training) and certain conversation/performance related skills. If you can find a talented military dorf with any scholarly skill, see if you can get him to teach at the library for a bit, then make him a champion so he can go teach the art of murdering gobos
Sometime in the future it's been hinted to by ToadyOne that certain building/actions will need to be unlocked through research by your dwarves (and visitors!). Anyone else found a good way to put libraries to good use until their intended use is coded in the game?