The Prague National Library serves three types of occupants - media & books, the public and the library staff - each with unique spatial typologies and functional needs. Using the bookshelf as the module for the building, the structure is based on a dense grid of columns, supporting both the bookshelves and the building as a whole. The heart of the library is the mass of book storage, protected from the exterior. Publicly accessible spaces - reading halls, lobby, theater, and lecture halls - are suspended within the lattice. Wrapping around this heart are the support areas, including offices and labs. The façade reveals these areas of human activity on the building's exterior skin. The Library is also an important institution in the urban fabric of Prague. It is innovative, but ties back to early 20th century Czech cubist tradition and recalls the city's soaring cathedrals.