There are so many things that excite us about the idea of having a library built into a staircase, including but not limited to having a staircase, living in one place long enough to invest in a staircase that doubles as a library, and putting our books on something that wasn't hauled in from the street.
What's even sexier is that this London staircase leads to a bedroom. If our trip to our bedroom was through a magical world of books every night, in an apartment with stairs, we'll we'd just be set for life.
Limited by space, we melded the idea of a staircase with our client's
desire for a library to form a 'library staircase' in which English oak
stair treads and shelves are both completely lined with books. With a
skylight above lighting the staircase, it becomes the perfect place to
stop and browse a tome. The stair structure was designed as an upside
down 'sedan chair' structure (with Rodrigues Associates, Structural
Engineers, London) that carries the whole weight of the stair and books
back to the main structural walls of the building. It dangles from the
upper floor thereby avoiding any complicated neighbour issues with the
floors below.

While we forsee a possible drunken trip hazard on the opposite-lenth stairs, we've never been so excited by architecture.
[Apartment Therapy via BoingBoing]