A book safe is such a fun project and adds a whole other level of cool to your bookcase. Keep all your trinkets and valuables out, in plain sight without anyone knowing they are there! DIY instruction (Cool Rooms In Houses)
If you have some hardcover books that no one’s interested in reading again, don’t toss ’em! Construct yourself a Book Hide. This involves hollowing out a book so you can keep valuables or secret stashes inside.