THE signing of the partial nuclear test ban treaty in the ,summer of 1963 prompted many arms control analysts, as well as many decision-makers and diplomatic negotiators concerned with East-West arms talks, to shift their attention from the now much-reduced problem of radioactive fallout in the atmosphere to the growing dangers of international strategic instability inherent in the proliferation of nuclear weapons. This concern was by no means new. The experts had been worried about it for several years. As early as 1959, the United Nations General Assembly had recognized that an increase in the number of nuclear states would aggravate international tension and render more difficult the attainment of arms agreements. Two years later, the Irish Resolution had called for ". . . the conclusion of an international agreement containing provisions under which the nuclear States would undertake to refrain from relinquishing control of nuclear weapons and from transmitting the information necessary for their manufacture to States not possessing such weapons, and provisions under which States not possessing nuclear weapons would undertake not to manufacture or otherwise acquire control of such weapons." I At the opening of the Eighteen Nation Disarmament Committee (ENDC) talks in Geneva in January 1964, both the United States and the Soviet Union included a non-proliferation agreement in the list of partial or collateral arms measures which they proposed for the consideration of the conference.2