The Cat Library is a modular bookcase designed as much for cats as it is for human users. Created by Belgian designer Corentin Dombrecht, this bookcase is incorporated with three modular parts made of birch plywood boxes that stack into a gridded storage system with a little staircase rising diagonally. The cool thing is that it can be set up backwards or forwards to conceal or reveal the paw-sized steps.
The bookcase has unusual storage spaces that double as a staircase for the animals, and the top shelf contains a built-in sitting basket. The staircase is designed so a cat can walk and even run aboard, without damaging the books that have been arranged neatly (as if that would happen at my house?). Read more here.