The library, which occupies the South-West side of the square, is designed to convey monumentality, in contrast with the residential character of the surroundings.
The horizontality of the facade is fragmented by vertical partitions, defining the four corners of the building and its main entrance, inspired by the Secession Building by Olbrich. The building features a slightly sloped Opus Siliceum base in basaltic stone and the arched windows provide ventilation to the archives stored in the basement.
As one of the functions of the library is to protect books and preserve culture, the building is reminiscent of funereal temples. In fact, the main lecture hall is domed by a pyramidal roof as a reference to the Mausoleum at Halicarnassus. Furthermore, immortality is symbolized by use of the cypresses trees on the side court and by the use of laurel leaves as decoration in the recessed entrance.
The rectangular rooms on the sides of the main façade are designed to contain the most precious books on stone bookshelves, visible from the outside as vertical bands in white marble with narrow windows in between, which filter the light. The vestibule which gives access to the main lecture hall via stairs is a direct reference to the Biblioteca Laurenziana’s one by Michelangelo.
The other two stairs connecting all levels of the building, which could contain glass lifts, are a new interpretation of those in Palazzo Barberini, designed by Bernini and Borromini.