Preservation rituals seem few and far between, but would gentle repose work? It's usually used on corpses but it is at heart a method of slowing entropy increase.
I am not going to say that you can't use Gentle Repose, but I won't say that the book will be fine and dandy if you do decide to use it. Like you said, it is only used for people, so you don't know the effects it might have on a book, if anything at all.
Wise words from someone wiser than I
"Each friend represents a world in us, a world possibly not born until they arrive, and it is only by this meeting that a new world is born."