Anyone know how to prevent book rot?

I was going through my bookshelf and I noticed that one of my hardcover books had a strange dark spot along the paper cover. So I pulled the book out and realized it was damp and had black splotches on the first 20-ish pages. It's been wet for about two weeks, since I put this thing as a block to keep the books from sliding around the shelf and filled it with water, which obviously leaked. Two of my books are wet [now somewhat dry] and they smell bad... Is there any possible way to reverse it or even make it smell better? If not, is it healthy for me to read out of the books even with the moldy damp smell?