Search engine results for occult libraries tend to have mostly commercial interests at play (vendors of trinkets and spell books and the like). Another issue I've run into is the genre tends to get treated like tabloids and scholarly resources are a bit muddled. I suppose it would be career suicide for some one with lofty academic credentials to actually write a book on spells or conjuring. Instead, credible authors tend to touch on the subject via a history-themed re-telling of Medieval Europe. Then there is the fixation on the sensational pieces such as the Codex Gigas -- an exhibit at a museum in Sweden. However, I would be interested to learn if there are actual physical libraries for the occult. This way one may obtain first/second-hand information on the texts rather than relying on experts who may choose or choose not to write a book on whatever sub-topic of the occult I'm interested in. In other words, I'm trying to peel back that layer of abstraction and read the things the occult authors were reading when they wrote the book.
This is where things seem a bit intimidating. If there are no reprints of the originals, the originals must be extremely old and fragile. Perhaps reading the originals is only feasible by pursuing a full-fledged degree and writing a whole dissertation.
Assuming we can agree on what authentic/original occult texts are (say 400 years old or older), how democratized are the occult texts and where might I visit some credible libraries if my resources and time would be that of a hobby rather than my mission in life?