The site for the Stuttgart City Library was chosen in Mailander Platz, an area that is perceived to be a future city centre growing out of the location of the library. With this in mind, the architects chose to physically express the importance of this cultural centre by giving the building a grand physical presence. The building takes the form of cube with an edge length of 45 meters.
It is constructed out of pale grey fair-faced concrete that visually frames an array of 9 x 9 frosted glass bricks. The shell is designed as a double facade that includes the glass brick level and an inner mullion/transom facade as the thermal building shell.
The form and symmetry of entrance of the building was inspired by the "Cenotaph for Newton" by Etienne Boullee, but the heart and core of the library follows the design of the ancient pantheon. Protected by a secondary facade, the cube-shaped room is situated in the middle of the building and is illuminated by a central roof light. In the center is a 1 m2 fountain that ties the space as a meditative area.
The gallery hall is a five-story space, square-shaped and surrounded by a shell of books. The interior circulation is arranged in a spiral among the reading gallery areas, designed to be flowing promenades flooded with light from the glass roof. The forum, a third central room, is located below the heart. This is an event room which is in proximity to the light-railway line that crosses the first and second basement floors.