With Mouse & Pen's cozy bookmarks, you get a beautiful front with cute designs, and a cozy and functional back with a shelf with empty book covers that you can fill with the books you plan to read. This bookmark features beautiful autumn colors and a cup of coffee along with the saying "Happiness is a cup of coffee and a good book". How to fill the back: Use an extra fine marker to write the titles of the books you want to read on the clear spines of the cozy shelf. When you're finished with a book, use a clear marker to color in the spine. Use different colors and you'll end up with a beautiful shelf full of your favorite books.