How to Make a Hollow Book Stash
Materials:
A book
White glue
Water
Paintbrush
Razorblades
The first step is to select a book to use. The best way to do this is to first examine the item you wish to conceal in the hollow book. With the dimensions of your target item, go to a used bookstore and buy the cheapest hardcover book you can that will fit your requirements, allowing one half inch of extra thickness.
Next, open the book and pick a spot about fifty pages in. Take a piece of paper larger than the book and sandwich it in the book at that point, so it overhangs the three open sides of the book. Now flip the book over.
Mix up a 50/50 mix of white glue and water. Using a paintbrush, paint the solution onto the edges of the clothed book. The piece of white paper should prevent the glue from being applied to the first fifty or so pages. Apply three coats of this solution, allowing drying time in between.
Now when you open the book, there should be fifty pages that are free to open, and one large block of paper glued together at the edges. Using a paper clip, clip the front pages to the cover so they cannot get in the way of the hollowing-out operation.
Now outline the space you desire to be hollow on the first page of the large block. Using the razor blade cut into the pages along your outline. It works best to cut about 25 pages at a time, depending on the thickness of your paper. Repeat this operation until you feel yourself poking through the last page.
Mix up some more glue/water mixture and paint it on the inside of the cavity you have created. This will keep the walls from fraying and the hollow book from falling apart. Then glue the back cover to the last page.
Once dry, if someone were to open the front cover of the book, the first fifty loose pages might provide the illusion of a real book, keeping your secret stash of valuables safe inside the hollow book.
Fill the hollow book with the items you wish to hide and put it on a bookshelf in the middle of other books. Now, it appears inconspicuous to anyone looking around the room. This works best with a book that looks horribly boring: calculus textbooks, histories of obscure events, and writing/grammar manuals work great as hollow books.