The Purpose of Endpapers
Endpapers play an important role in the structure of a hardcover book. They help securely attach the inside pages to the cover, keeping the book block firmly in place. An endpaper is a spread made up of four pages at the front and four pages at the back of the book. Three of these pages can be printed if desired. The fourth page is glued to the inside of the hardcover board, ensuring a strong bond.
For thinner books, it is possible to use so-called glued-in endpapers. In this case, there are no separate endpapers — instead, the first and last pages of the book block are glued directly to the inside of the cover, making them no longer visible.