Rotblat, Sir Joseph, 1908–2005, British physicist and anti-nuclear weapons activist, b. Warsaw, Poland; grad. Free Univ. of Poland (M.A., 1932), Univ. of Warsaw (Ph.D., 1938), Univ. of Liverpool (Ph.D., 1950). He went to Liverpool on a research fellowship in 1939 and five years later traveled to New Mexico to join the Manhattan Project team that developed the atomic bomb. On learning that Germany could not also produce such a weapon, a supposition that originally had been used to justify development of the bomb, Rotblat became (1944) the only scientist to leave the project. He went back to England, became a British subject, and returned to the Univ. of Liverpool (1945–49) as director of research in nuclear physics, later serving (1950–76) as professor and specialist in medical physics at the Univ. of London. Rotblat cofounded (1946) the Atomic Scientists Association and, along with Einstein and other scientists, signed (1955) a document drawn up by Bertrand Russell that decried nuclear proliferation and warned of the dangers of nuclear war. This manifesto led to the founding (1957) of the Pugwash Conferences on Science and World Affairs. Held in Nova Scotia, these international forums focus on eliminating nuclear arms and have been credited with laying the groundwork for a series of treaties and conventions banning various tests and weapons. Rotblat served as conference secretary-general (1957–73) and president (1988–98). In 1995 he and the Pugwash Conferences were awarded the Nobel Peace Prize. Rotblat also wrote and edited many books on nuclear physics, nuclear disarmament, and the search for world peace. He was knighted in 1998.