Peierls devotes Chapter 12 of Bird of Passage to 'Problems of nuclear weapons', explaining his concern with postwar dangers and the international problems involved. He writes with special reference to the Pugwash conferences which remained a lifelong commitment at national and international levels, but he also joined or was sought out by many other organizations. He wrote and lectured extensively on anti-nuclear themes and disarmament; there is a little documentation of this aspect of his activity but by no means a full record.