This is pretty amazing: https://www.theguardian.com/books/2019/apr/10/extraordinary-500-year-old-library-catalogue-reveals-books-lost-to-time-libro-de-los-epitomes
That's just mind-boggling... Somebody tried to put together something akin to the Library of Congress that long ago (I'm sure there are non-US-centric equivalents, I just don't know them)
That's amazing! Can you imagine the bizarre life of that book, itself lost to the world; until finally someone cracks it open and realizes what a treasure they've found.