It would be very nice to be able to have more control over where books end up, especially since "visitors steeling books" seems to be a thing.
I was given to understand that visitors could also
bring books? Those have to come from somewhere. Letting them walk off with your books seems a logical price to pay for that feature.
My suggestion for upgrading the interface to work around the issue of visitors leaving with books would be something to the effect of "minimum number of copies." That way my scribes automatically produce two or three copies so I don't have to worry about a wandering scholar walking off with my only one.
As a separate suggestion, make sure the scribes prioritize books to copy with the metric of "book with lowest number of copies gets copied first."
Maybe a manual "copy this book" could be helpful.
This! I need a medical library! All my medical staff are discussing Geology and reading books about Surveying instead of the diagnosis and suturing books...
At least a partial solution to
this problem might be having scholars generally prefer to discuss topics they already know about (i.e. improve skills they already have) rather than diversify. That way you could assign a doctor as a scholar in the library and that dwarf will want to think/talk/write/read about (and thus improve) medical skills rather than chemistry or mechanics. Since discussions are inherently interactive between more than one person, this dwarf's preference will also impact other dwarves you assign, especially ones that have no scholar-relevant skills (and thus no preferences under this metric), allowing you to train doctors that way. All of this will probably be impacted by needs like "learn something new."
EDIT:
This thread about research labs might also be relevant.