Anna Marie Duke (December 14, 1946 - March 29, 2016), known professionally as Patty Duke, was an American actress. Beginning her acting career in commercials and playing bit parts in television and movies, her breakthrough role was as Helen Keller in the Broadway version of "The Miracle Worker" (1959 - 1961). For the 1962 film adaptation, Duke reprised her role, which won the Academy Award for best supporting actress - at age 16, she was the youngest person ever to win an Oscar (a record later broken by Tatum O'Neal in 1973). Other early films included Billie (1965), Valley of the Dolls (1967), and Me, Natalie (1969). On television, Duke starred in the popular teen sitcom The Patty Duke Show (1963 - 1966), playing a dual role and garnering the first of ten Emmy nominations. She won Emmys for her roles in television film My Sweet Charlie (1970), miniseries Captains and the Kings (1976), and the 1979 TV movie version of The Miracle Worker (1979), this time portraying Annie Sullivan. She served as president of the Screen Actors Guild from 1985 - 1988.

Off-screen, Duke's life was often tumultuous. Born in Elmhurst, New York, to Frances Margaret (McMahon), a cashier, and John Patrick Duke, a cab driver and handyman, her acting career began at age eight when she was turned over to her brother Ray Duke's managers, John and Ethel Ross, who changed her name and engaged in exploitative behavior. Duke was married four times: to director Harry Falk from 1965 - 1969; to writer Michael Tell in 1970 (with whom she became mother to actor Sean Astin); to actor John Astin from 1972 - 1985 (with who she became mother to actress Mackenzie Astin); and to drill sergeant Michael Pearce from 1986 until her death (with whom she had two stepdaughters and an adopted son Kevin). In 1982, she was diagnosed with bipolar disorder, which was the subject of her second book, "A Brilliant Madness: Living with Manic Depression Illness" (1992). Duke was also a political advocate for issues such as the ERA (Equal Rights Amendment), AIDS awareness, and nuclear disarmament. She died on March 29, 2016, in Coeur d'Alene, Idaho, of sepsis from a ruptured intestine.