A wet book that goes unchecked can quickly become covered in mold and mildew, ruining it forever. Even a book that gets slightly damp can suffer this fate. Don't let this happen to your precious tome; if you notice that your book has somehow gotten wet, take immediate action using the following steps.
If you spill water on a book and can attend to it immediately, pick up the book and set it down away from the puddle. Quickly grab several paper towels and blot the pages dry. Dab the pages with the paper towels and press down firmly, but do not wipe. Keep this up until the paper towels stop absorbing moisture.
If you have a book that has been wet for some time or was recently dried using the method described in Step 1, set up your ironing board. Warm the iron to a medium setting.
Place a wet book on the ironing board on its back cover. Open the book to the first damp page, and cover that page with a facial tissue. Quickly and gently iron the page through the tissue.
Flip through the book one page at a time, ironing each page through a facial tissue. The heat will dry the pages quickly and will smooth out pages that have warped after beginning to dry.
Repeat the ironing process with each book.
If the dried book smells a little like mildew but doesn't show any other signs of mildew, leave it outside for a few hours on a warm, dry, sunny day. If possible, stand the book up on its end and fan out the pages a little bit so that all of the pages have an opportunity to air out.