Accustomed as he was to a rigorous diet of the classics, it was perhaps not surprising that, despite enormous success, he bolted from "Bonanza" after the 1964-65 season, criticizing the show's simple-minded content and lack of minority actors. He also hated his character calling Lorne Greene "Pa," as both were adult men, and asked to stop wearing his toupee. The show soldiered on, remaining popular until its end in 1973. Mr. Roberts never returned.