You hear the click as the bookcase slides back into place, hiding Katie's Secret Room from everyone who might come through the library. Relieved to see noone is here to discover your secret, you look around the dusty library. It's walls are full of books up to the ceiling, and it's floor is occupied by desks. Across the room from you is the door to the Archives, where Jesse's old junk is hidden while still keeping it accessible to him and whoever else feels like looking around through it. To the left is the door out into the Sitting Room, where you can gain access to the rest of The Mansion, including the Room of Doors, which will lead you to other places in the dream world.