acting range. In a newspaper interview, he said, "I haven't grown at all since the series began...I have an impotent role. Wherever I turn there's the father image." Finally, after disagreements with writers and producers over the quality of the scripts, characterization, and Bonanza'''s refusal to allow him to perform elsewhere while on contract, Roberts "turned his back on Hollywood wisdom and well-meant advice," and left, largely to return to legitimate theater.Henry Darrow archival interview; USA Today, January 25, 2010) Roberts fulfilled, but did not extend his six-year contract for Bonanza, and when he left the series, his character was eliminated with the explanation that Adam had "moved away." Later episodes suggested variously that Adam was "at sea", had moved to Europe, or was on the East Coast, running that end of the family business. The last episode Pernell Roberts worked on was "Dead and Gone", air date April 4, 1965. He appeared in the next two that aired, which were filmed prior to "Dead and Gone" — "A Good Night's Rest", air date April 11, 1965, and "To Own The World", air date April 18, 1965. Adam Cartwright was mentioned on occasion in the series (including a 1967 episode that did not air until April 4, 1971 ("Kingdom of Fear"). In television interviews, Roberts said that he would have stayed with Bonanza, had he been allowed to do so on a part-time basis to enable him to return to theater. Bonanza producer David Dortort described Roberts as "rebellious, outspoken... and aloof," but as one who "could make any scene he was in better...". In a later archive interview, he regretted not having insisted on a "marriage for Adam" and having Roberts continue on the show as a semiregular. He added, "I must confess..I was too hard on him. I did not appreciate him. I knew he was good, but I didn't realize he was that good...none better." In the last two Bonanza movies that aired on NBC in the early 1990s, the story line stated that Adam, now in Australia, had equaled his father's success, dominating the engineering/construction business. Roberts was the only accomplished singer of the original cast, though David Canary, who joined Bonanza in 1967, had a background in voice and performed on Broadway. During Roberts' Bonanza years, he recorded Come All Ye Fair and Tender Ladies, a folk music album, which AllMusic calls "...the softer, lyrical