It is a real shame when old books get damp. Sometimes they are dropped in the bath, and sometimes they sit in mouldy rooms for thirty years, but either way the damage is irreversible. The pages yellow and darken. The spines break, and the pages bend. Covers crack and fade. But sometimes, something glorious happens. Sometimes the water stretches reveals new parts of the story.
Because every piece of creative writing has alleyways of narrative and description that never made the final cut. You can edit the different paths out of the writing, but the words remember.
This takes time. You cannot sling your paperback in the bath, and unlock a new end to your summer reading. The process happens like mushrooms growing in the dark. But experts can grow a copy of Dickens where a talking cat meets Oliver. Read soliloquies by Hamlet never performed on the stage. Discover proof of interstellar transport in a book of short stories by Arthur C. Clarke.
So if your house floods, and trashes your books, do not throw them out. Leave them a month, then have a look. You may have to read them from cover to cover to find if there are any changes, and end up with nothing but musty hands.
However, you may end up in the world of an imagination shared only between the author and you. One that may only last for a few months before the paperback rots away, and returns to the ether of imagination, until the pages of another soggy flourishes the story to life once again.