William Sylvester was an American television and film actor. His most famous film credit was Dr. Heywood Floyd in Stanley Kubrick's 2001 A Space Odyssey. Sylvester declined to reprise his role in the film 2010: The Year We Make Contact, in which he was replaced by Roy Scheider. Scheider is generally regarded as having been mis-cast for the part, with the vast difference in mannerisms and appearance between Sylvester and Scheider such that the roles have periodically been mistaken for different characters.
Born in Oakland, California and married at one time to the British actress Veronica Hurst, he moved to England after World War II and became a staple of British B films at a time when American and Canadian actors were much in demand in order to give indigenous films some appeal in the United States.
As a result, he gained top billing in one of his very first films, House of Blackmail, directed by the veteran filmmaker Maurice Elvey, for whom he also made What Every Woman Wants the following year. He also starred in such minor films as The Stranger Came Home, Dublin Nightmare, Offbeat, Information Received, Incident at Midnight, Ring of Spies and Blind Corner.