Malcolm Toon was a leading State Department expert on the Soviet Union and Eastern Europe during the Cold War, a blunt ambassador with a reputation as a hard-liner in diplomatic duels with Communist governments. In nearly 35 years as a Foreign Service officer, he was ambassador to Czechoslovakia, Yugoslavia, Israel and most notably, the Soviet Union. Yet for all his prominence in the halls of power, in Washington and Moscow, his death at a hospital in Pinehurst, N.C., eight years ago at 92 — some 30 years after he had retired and many years after he had dropped from public view — went largely unreported. Mr. Toon was fluent in Russian, and his appointment in the last weeks of President Gerald R. Ford’s administration was in line with a tradition of experienced diplomats serving as the American envoy in Moscow. But the Russians considered him hostile and delayed formally approving his appointment. In his first months in office, in 1977, President Jimmy Carter backed off from Ford’s selection of Mr. Toon, but then went ahead with it. Malcolm Toon was one of four children of George Toon, a stonecutter, and his wife, Margaret. He was born on July 4, 1916, in Troy, N.Y., a few years after his parents had emigrated from Scotland. The Toon family returned there when he was 6, then came back to the United States and settled in Northborough, Mass., about 50 miles west of Boston. Mr. Toon graduated from Tufts University in 1937 and received a master’s degree from its Fletcher School of Law and Diplomacy in 1938. He commanded a PT boat in the Pacific during World War II, then joined the State Department. He served in Poland, Haiti and Hungary, received Russian-language training and had stints in the Moscow embassy in the 1950s and ’60s. Mr. Toon was the third-ranking embassy official in Moscow in 1965 when a Communist publication accused him of heading an American spy ring, evidently a response to Washington’s previous expulsion of Russia’s No. 3 diplomat there in a spy case. The accusations were denied, and Mr. Toon was not expelled. In the late 1960s, he headed the State Department’s office of Soviet affairs. President Richard M. Nixon named Mr. Toon ambassador to Czechoslovakia in 1969. He became ambassador to Yugoslavia in 1971 and helped promote American investments there. He later told of forging a close personal relationship with the Yugoslav leader Marshal Tito. Mr. Toon was named ambassador to Israel in the spring of 1975 by President Ford. Mr. Toon was survived by his son, Alan; his daughters Nancy Toon and Barbara Lindenbaum; and three grandchildren. His wife, the former Elizabeth Jane Taylor, died in 1996 at 77.