"Small Book, Secret Box. "
Here's how to hide a letter or a piece of jewelry in the middle of your bookshelf. This book has been transformed into a box by the bookbinder, so it blends in with the other books. It's a very fine piece of work in a 19th-century book. Moreover, it's in excellent condition. 
Le Magazine de PROANTIC
TRÉSORS Magazine
Rivista Artiquariato