Hiding Place in a Book
You’ve probably seen in countless movies and TV shows of people hiding stuff in books. It could be a gun, a flask of whiskey, or whatever. The point is, those book hiding places are really, really cool. And that’s exactly what the OP was thinking, which was why they tried recreating what they saw on TV in the first place.
Now, we’re not sure how difficult it is to cut out a portion of the inside of a book, but judging by what we see in the picture above, it looks pretty complicated. Or maybe this person didn’t use the right tools to get the job done.