Like the photo library and the collection of works of art, the Foundation's library is based on the collection of books which Roberto Longhi left to the institution when he died.

When Roberto Longhi died there were from 20 to 25,000 books in his library divided into the following sections:

Renaissance biographical sources;

Chronicles of foreign visitors to Italy;

Guides to cities, provinces and regions;

Catalogues of museums and private collections;

Sales Catalogues;

Catalogues of exhibitions held in Italy and abroad;

Monographs about old masters;

Monographs about modern artists

Books concerning modern and contemporary art movements;

Catalogues of periodic exhibitions.

There was also a section of handbooks (dictionaries, textbooks, repertories and encyclopedias.