Richard Henry Popkin (December 27, 1923 – April 14, 2005) was an American academic philosopher who specialized in the history of enlightenment philosophy and early modern anti-dogmatism.
Among his honors, Popkin was awarded the Nicholas Murray Butler Medal by Columbia University and was a fellow of the American Academy of Arts and Sciences.
Popkin published two autobiographical writings: Intellectual Autobiography: Warts and All in The Sceptical Mode in Modern Philosophy.
Beyond his philosophical works, he is noted for writing The Second Oswald (1966), questioning the Warren Report lone gunman explanation of the John F. Kennedy assassination.
Popkin's theory was that a look-alike of Lee Harvey Oswald was the actual assassin of Kennedy.