The Foundation Library, run by the Lelio Basso Library staff and constantly expanded and updated through donations and a targeted acquisition policy, has been regularly open to the public since 1975.
A patrimony of over 100,000 volumes and 5,000 periodical titles (200 of which are ongoing) specialized in historical sciences, law, sociology and political science, dealing with the central issues of the origins and evolution of democracy, socialism and mass movements. The library has works ranging from the sixteenth century to the present day and includes a significant number of primary historical sources.
Internationally, the library provides search tools that cover Europe and America, Asia and Africa. Of particular note is the large collection of books on Latin American countries, dating back to the late 1960s as a result of Lelio Basso’s work in support of peoples oppressed by dictatorships, which culminated in the establishment of the Russell Tribunal II. It has been updated and expanded in the following decades.