Fifty years after his death, the creator of psychoanalysis is still the subject of intense debate. Was Freud right or wrong? NOVA profiles the enigmatic man and his controversial legacy.

Harvard chemist George Kistiakowsky was an anti-Bolshevik soldier in 1919 Russia, an atomic bomb scientist at Los Alamos, a presidential advisor in the Eisenhower White House and an arms control activist. Shortly before Kistiakowsky death, he recounts his eventful career to interviewer Carl Sagan.