Lately, I've been rereading books by Mary Stewart. Many of the hardbacks I have are from the 1950s and 1960s and are getting a bit fragile.
This is how my copy of Nine Coaches Waiting looked after I pulled the drooping binding together.

I ended up having to tape the spine to the back cover to make sure it didn't fall off, although I'm certain that regular tape can't be good for the health of the book. Even so, pieces of the spine's backing fell off. The below picture is of a section that slid out from the spine while I was reading the book. It feels a bit like thin cardboard.

I have to admit that I was nervous reading the book and treated it very, very gently. Yet at the same time, I found it so cool to be reading a physical copy of a book that was printed in 1959. And as an author, I'm impressed by the fact that my copy was part of a sixth printing of the book, which was originally released in 1958. That's one popular book!