Pernell Elven Roberts Jr. was an American stage, film, and television actor, activist, and singer. In addition to guest-starring in over 60 television series, he was best known for his roles as Ben Cartwright's eldest son Adam Cartwright on the Western television series Bonanza (1959–1965), and as chief surgeon Dr. John McIntyre, the title character on Trapper John, M.D. (1979–1986).

Bonanza is an American Western television series that ran on NBC from September 12, 1959, to January 16, 1973. Lasting 14 seasons and 431 episodes, Bonanza is NBC's longest-running Western, the second-longest-running Western series on U.S. network television, and one of the longest-running, live-action American series. The show continues to air in syndication. The show is set in the 1860s and centers on the wealthy Cartwright family, who live in the vicinity of Virginia City, Nevada, bordering Lake Tahoe. The series initially starred Lorne Greene, Pernell Roberts, Dan Blocker and Michael Landon and later featured Guy Williams, David Canary, Mitch Vogel and Tim Matheson. The show is known for presenting pressing moral dilemmas.