He made important contributions to nuclear physics, both before and after working during the war on atomic energy problems at Liverpool and at Los Alamos. This included observations on the angular distribution of protons from the (d,p) reaction, which led to an important tool for determining the spin and parity of nuclear levels. He worked on the medical applications of nuclear physics, and later on the biological effects of radiation. His outstanding distinction is in his work for the Pugwash Conference on Science and World Affairs. He was one of the founders of these conferences, and for the past 37 years has been untiring in his support and enthusiasms [sic] for the conferences, which have enabled scientists from all over the world and with opposing ideologies to talk objectively about the issues dividing them. His untiring devotion to this cause and his inspiration have been vital for the development and continuing existence of the conferences.