Gaunt and incisive, this distinguished, red-haired character player was a stage actress of formidable experience, trained in the classics. Beatrice Straight began doing occasional feature film and TV work in the early 1950s, but was almost entirely unknown to the nationwide public when she won the Best Supporting Actress Oscar for her stellar work in "Network" (1976).Related to America's most socially prominent families (she was a Whitney on her mother's side), Straight made her Broadway debut in "Bitter Oleander" in 1935 and subsequently acted on stage in "The Possessed" (1939), "Twelfth