On the occasion of the Centenary recurrence of Vito Volterra’s Presidency of the Italian Society of Sciences (1919-1920), the National Academy of Sciences said of XL celebrates the great mathematician, physicist and policy-maker. A meeting will be held on the library of the Academy at Villa Torlonia, taking place from 10 a.m onwards. The meeting will be chaired by professor Giorgio Parisi, one of the XL and current President of the Lincei National Accademy. The lecturers will be Elisabetta Strickland, Angelo Guerraggio, Giovanni Paoloni, Giovanni Battimelli and Annibale Mottana, current president of the National Academy of Sciences.