Waterproof books, used mainly by skin divers and foul-weather hikers, are finding a new audience among people who simply enjoy a nice warm bath.

The new dunkable books are made not from trees, but from plastic resins and inorganic fibers.

Melcher Media, a New York-based publisher, is promoting books that are manufactured using a technology it calls “Durabooks.” The books’ pages don’t absorb water, and they stretch instead of tearing. Other companies make waterproof books with standard wood-based paper that is heavily laminated in the printing process.