Kennan, George Frost (1904- ), American diplomat, born in Milwaukee, Wisconsin, and educated at Princeton University. He began his diplomatic career in 1927 in Hamburg, Germany. His four tours of duty in the Soviet Union included service as the U.S. ambassador in 1952; he retired from the foreign service in 1953. As a result of his experience, Kennan was regarded as an authority on the USSR. In 1961, recalled to service by President John F. Kennedy, he began two years of duty as ambassador to Yugoslavia. Also an educator, he was a member (1953-74) of the Institute for Advanced Studies in Princeton, New Jersey. As an author, he won both the Pulitzer Prize in history and the National Book Award for volume 1 of his two-volume work Soviet-American Relations: 1917-1920, entitled Russia Leaves the War (1956); he won the Pulitzer Prize in biography and the National Book Award for Memoirs: 1925-1950 (1967). Volume 2 of the first-named work is Decision to Intervene (1958); his autobiography is continued in Memoirs: 1950-1963 (1972). His other works include Cloud of Danger (1977), an assessment of U.S. foreign policy.