Jack Foust Matlock Jr. (born October 1, 1929) is an American former ambassador, career Foreign Service Officer, teacher, historian, and linguist. He was a specialist in Soviet affairs during some of the most tumultuous years of the Cold War, and served as the U.S. ambassador to the Soviet Union from 1987 to 1991. Matlock became interested in Russia as a Duke University undergraduate, and after studies at Columbia University and a stint as a Russian-language instructor at Dartmouth College, entered the Foreign Service in 1956.
https://en.wikipedia.org/wiki/Jack_F._Matlock_Jr.