1963 US, USSR reach Hotline and Modernization Agreements. 1963 Limited Test Ban Treaty signed by US, USSR, Britain. 1967 US, USSR, Britain ban atomic arms in outer space. 1968 US, USSR, Britain sign Non-Proliferation Treaty. 1969 US-USSR Strategic Arms Limitation Talks begin. 1971 US, USSR sign Accidents Measures Agreement. With Britain, they ban nuclear weapons from seabeds. 1972 US, USSR sign Anti-Ballistic Missile Treaty and Pro- tocol and SALT I Interim Agreement, freezing number of ballistic missile launchers at existing levels. 1973 NATO and Warsaw Pact begin talks in Vienna on troop reductions in Central Europe. 1974 US and USSR draw up Threshold Test Ban Treaty, but US does not ratify. 1975 Thirty-five governments including US and USSR sign Helsinki Declaration, which calls for advance notice of military maneuvers in Europe. 1976 US, USSR begin talks on banning chemical weap- ons. (Talks suspended in 1980.) Superpowers draw up Peaceful Nuclear Explosions Treaty, but US fails to ratify. 1977 US, USSR, Britain begin talks on comprehensive nuclear test ban treaty. Talks suspended in 1980. 1979 Presidents Carter and Brezhnev sign SALT II treaty, setting ceiling of 2,400 strategic missiles and bombers on each side, to be reduced to 2,250 by 1981. After Soviets in- vade Afghanistan, US withdraws SALT II from Senate, but both governments say they will abide by provisions. In December NATO decides to deploy 572 US Pershing II and cruise missiles in Europe starting in late 1983 to counter threat from Soviet SS-20s targeted on European cities. NATO twins decision with offer of talks. 1981 Superpowers meet in Geneva for talks on limiting medium-range missiles in Europe. US offers ``zero op- tion'': Moscow would dismantle existing SS-20s; US and NATO would drop planned Pershing and cruise deployments. 1982 Brezhnev announces unilateral freeze on medium- range missile deployments west of Ural Mountains, but US says SS-20 deployments will continue. Superpowers open Geneva talks on strategic missiles (START or Strategic Arms Reduction Talks). Moscow re- jects zero option in Intermediate-range Nuclear Forces talks (INF). In START, Reagan proposes one-third cut in US and Soviet intercontinental warheads, with missiles on each side to be reduced to 850. USSR rejects idea, offers cuts to 1,800 strategic missiles on each side. US and NATO reject Soviet proposals to freeze both European- based medium-range and strategic missiles. At UN, Brezhnev renounces first use of nuclear weapons. Soviet leader Andropov offers in December to cut Euro- pean-based SS-20s to match sea and land-based missiles in British and French independent nuclear forces. Pro- posal is rejected by US, Britain, and France. 1983 In START, US offers concessions on missile num- bers, calls for mutual ``build-down'' under which both sides would dismantle a larger number of existing war- heads than the number of new weapons deployed. Soviets reaction is negative. US says negotiator Paul Nitze and Soviet envoy Yuli Kvitsinsky reached informal INF agreement during July 1982 ``walk in woods'' for each side to cut back to 75 me- dium-range missile launchers. US, USSR disown idea. Reagan proposes to speed research into defensive space weapons -- his Strategic Defense Initiative -- to provide shield against atomic attack. US offers INF interim agree- ment for both sides to cut to lowest negotiable levels. US says it would agree to global ceiling of 420 medium- range warheads on each side. Moscow offers to scale down to 120 SS-20s in Europe, excluding bases in Soviet Asia. First of US cruise missiles reach Britain; first Pershing IIs reach West Germany. Moscow suspends INF, refuses to continue START. Andropov announces end to unilateral missile freeze west of Urals, speed-up in preparing to deploy short-range mis- siles in East Germany and Czechoslovakia, and plan to move more submarine-based nuclear missiles close to US shores. 1984 European Disarmament Conference opens in Stockholm to consider confidence-building measures. Dutch government agrees to deploy 48 cruises, but only if Moscow should continue to increase SS-20 buildup. Agreement to modernize Washington-Moscow ``hot line.'' Moscow calls for September space weapons talks. US asks to discuss missiles, too. Kremlin backs off. Reagan meets Gromyko, suggests ``umbrella'' format for arms talks and regular meetings between US, Soviet officials. Following Reagan's re-election, superpowers announce Shultz and Gromyko will meet in Geneva on Jan. 7 and 8 to discuss terms for resuming arms negotiations. US says Moscow has increased SS-20 total to 387.