Priscilla Johnson McMillan (born Priscilla Mary Post Johnson) (July 19, 1928 – July 7, 2021) was an American journalist, translator, author, and historian. She was a Center Associate at the Davis Center for Russian and Eurasian Studies at Harvard University.At the beginning of her career she worked for Senator John F. Kennedy and saw him informally for several years thereafter. During the late 1950s she served as reporter in Moscow for the North American Newspaper Alliance, and interviewed Lee Harvey Oswald as he was defecting to the Soviet Union in 1959. Following the assassination of President Kennedy by Oswald, she became friendly with Oswald's widow, and in 1977 published the acclaimed study Marina and Lee: The Tormented Love and Fatal Obsession Behind Lee Harvey Oswald's Assassination of John F. Kennedy. She also published Khrushchev and the Arts: The Politics of Soviet Culture, 1962–1964 (1965) with co-editor Leopold Labedz and The Ruin of J. Robert Oppenheimer and the Birth of the Modern Arms Race (2005) about the Oppenheimer security hearing. She was the only individual who, to a significant extent, personally knew both President Kennedy and his killer.