An intense, brooding leading man and character actor on stage and in television, Pernell Roberts rose to fame as Adam, eldest son of the Cartwright clan, on “Bonanza” (NBC, 1959-73), one of the longest-running and most popular television series in history. He left the show in 1965 due to conflicts with producers over the show’s writing, and became a regular face in guest-starring roles on television and the occasional film. But in 1979, he returned to television stardom with the lead role in “Trapper John, M.D.” (CBS, 1979-1986), a medical drama based on the Korean War doctor played by Elliott