The library made a qualitative leap forward with the acquisition of the books and materials belonging to the great Roman archaeologist Rodolfo Lanciani
The library continued to expand from 1929-1939. Extending to the Torre della Biscia (the tower on the south end of the building), the library was given the collection of Rodolfo Lanciani (1845-1929), a rich patrimony of drawings, manuscripts, prints and notes on Roman topography. Additional donations followed: the Alfredo Castellani Archive (1856-1930) in 1930, the music collection of Alessandro Vessella (1860-1929) in 1933, and the Corrado Ricci Archive in 1934.
Portrait of Rodolfo Lanciani with the Imperial Forum behind him, in a 1934 print by painter and engraver Valerio Fraschetti, today in the Lanciani Archive, BiASA