* PURPOSE -- The INF (Intermediate-Range Nuclear Forces) negotiations are intended to limit medium-range nuclear missiles in Europe.

* HISTORY -- Negotiations began in Geneva in November 1981 and were suspended in November 1983 when the Soviets walked out. Little had been achieved.

* SOVIET MISSILES -- SS20 mobile missiles with three warheads each and older SS4 single-warhead missiles, both capable of hitting major Western European targets.

* U.S. MISSILES -- Pershing 2 missiles, single warhead, capable of reaching targets in the western U.S.S.R. but not Moscow, and cruise missiles, single warhead, slow and low-flying.

* DEPLOYMENTS -- The United States and NATO have 54 of a planned 108 Pershing 2s deployed and 48 of a planned 464 ground-launched cruise missiles. The Soviets have 120 SS4s in Europe and 387 SS20s.

* SOVIET PROPOSAL -- Initially, an offer to cut SS20s targeted on Europe to match the number of British and French sea- and land-based missiles, allowing for no U.S. medium-range missiles. This was rejected by the West and the Soviets then offered to cut SS20s to 120, not including those deployed in Asia.

* U.S. PROPOSAL -- Initially, the so-called zero-zero option, under which the United States would deploy no medium-range missiles if the Soviets destroyed all medium-range missiles. This was replaced by a proposal that as an interim step, each side observe a 420-warhead global limit, including Soviet medium-range missiles based in Asia.

* CHIEF ISSUES -- West's insistence on deploying Pershing 2 and cruise missiles in Europe; Soviet insistence on counting French and British sea- and land-based missiles in the West's total and refusal to include SS20s targeted on Asia in the Soviet total.