Outside it's a book, inside it's a box, with a secret-compartment, and another, and another.
Incorporating a magnetic-lock, a gravity-lock, and a slide-lock it's designed to be "found-out" far enough that a person stops looking for the extra-hidden spaces.
I would have taken more photos but I've had camera-problems and I wasn't sure of actually finishing it.
*I started with a half-price hardback which I didn't mind cutting-up.
*The insides were built as a wooden-box, and I'm keeping the way that works secret.
*The magnets used in the secret-lock were extracted from a Geomag set.
*The lining was made from a polyester-tie.