The author is Secretary General of the Pugwash Conferences on Science and World Affairs and Professor of Physics at the University of Milan, Italy. Pugwash was awarded Nobel Peace Prize in 1995. Following are extensive excerpts from a paper Professor Cotta-Ramusino presented to the conference on 'Perspectives for a world free from nuclear weapons and for integral disarmament' at Vatican City on 10 November 2017. - The Editor