I grew up with these as an Xer, so I know what it was like trying to find a book with them. Modern library catalogs are so much nicer to use. But I'm still a huge fan of the Dewey Decimal System. And when you find a library that still stamps the due date in the books, it's great seeing the last time someone has borrowed a book, especially if its been a long time, I borrowed one book of essays in grad school 2019, it was acquired in 1988 and I it felt great to be the first person to borrow it. The book wasn't even one I was looking for but it was on the shelf beside the one I was after and it looked interesting, and it turned out to be great.