Books are bound in two ways, with glue or with stitches. Avoid the ones bound with glue.
Check your bookshelves or go to your local bookstore and collect books about art, science, nature, etc.
Open a book and locate the stitches between every 8th page (or so). Cut the stitches and set aside the pages you unbind.
Sort through the sheets you've unbound and you could find a work of art.
Collect at Bookstores Regularly
Post what you find #deadbookstore