This hidden door bookcase leads from an office to the guest quarters in a private home in Alameda, Calif. Designed by Mark Dutka of InHouse Design Studio, it’s made of rift oak with a natural finish, and is just one part of a highly complex design which covers every inch of the room’s walls. It was quite the challenge, but Dutka's specialty is the design of custom cabinetry solutions for specialized residential environments. Our question is, what’s the secret password?