Oh, you know the kind. Where you pull a particular book and the whole case opens to reveal a secret passageway and all kinds of mysterious and surreptitious doings and goods behind?
If you've got the space (and the secrets), you can have one, too.
Dude, 'member Webster? Little guy gets adopted by rich parents, and lives in a big old Victorian house, complete with secret passages and an old butler's elevator that he could move around in? I blame those pathways and a lifelong interest in Clue (both the boardgame and the awesome 1985 film adaptation, which my childhood Matt Davish had on Betamax) for a tiny obsession with passageways, hidden doors, and all around Sherlock Holmes-y secret goodness.
So this hidden bookcase door is, you know, crazy amazing.