* PURPOSE -- The Strategic Arms Reduction Talks (START) are intended to reduce Intercontinental Ballistic Missiles and other long-range systems launched from land, sea and air.

* HISTORY -- After the Carter administration failed to submit for Senate ratification the 1979 SALT II treaty that would have limited strategic arms, START negotiations began in Geneva in June 1982 but were suspended in December 1983 after making little headway.

* WEAPONS -- Estimates vary but the United States says it has 7,830 strategic warheads and the Soviets 8,377. Each side has a full array of delivery vehicles, including missiles with up to 10 warheads each and pinpoint accuracy, long-range bombers carrying bombs and air-launched cruise missiles, and submarine-launched missiles.

* DEPLOYMENT -- The U.S. reportedly has 304 Poseidon missiles and 288 Trident missiles based on submarines. Its land-based missiles include 1,000 Minutemen and it has 271 strategic nuclear bombers. The Soviets reportedly have more than 650 highly powerful and accurate SS18s and SS19s and about 700 older missiles; 981 sea-based nuclear missiles and 143 long-range nuclear bombers, plus 230 bombers that the United States considers strategic but the Soviet Union does not.

* U.S. PROPOSAL -- Initially, reducing land- and sea-based warheads to about 5,000 and then missiles to 850 but not reducing bombers. Later Washington proposed "tradeoffs" (U.S. cuts in heavy bombers and cruise missiles in return for reducing destructive power of Soviet missiles) and "build-down" (more existing missiles removed than new ones deployed).

* SOVIET PROPOSAL -- Cuts by about one-fourth in nuclear missiles and bombers, to a total of 1,800 on each side, and unspecified limitations on the number of strategic nuclear warheads and bombs, as well as a freeze on production and deployment of new weapons.

* CHIEF ISSUES -- The greater explosive power of Soviet missiles, the role of U.S. and Soviet bombers, the status of U.S. air-launched cruise missiles, and future production.