For over forty years, nuclear weapons were a major concern of Andrei Dmitrievich Sakharov. A brilliant physicist whose work was instrumental in the creation of the Soviet hydrogen bomb, Sakharov was led by his concern about the dangers of nuclear weapons and the threat of nuclear war to become a courageous activist for peace and disarmament, as well as for human rights (A 1989 talk by Sakharov is reprinted in PHYSICS TODAY, July 1999, page 22; for more on Sakharov, see PHYSICS TODAY, August 1990, which was a special issue devoted to him; also see the American Institute of Physics's Center for the History of Physics on‐line exhibit on Sakharov at In his lifetime he saw the problems and dangers associated with creating such massively destructive weapons through the highly refracting lens of the cold war. That war is over. The Soviet Union no longer exists. But great dangers remain, albeit mutated into new forms. We still face grave perils.