No actor showed the commercial potential of blue-chip British classical training like Patrick Stewart. With style, technique and the most minutely self-aware, almost vaudevillian sense of mimicry, Shakespearean thesps can turn their hand to American movies and high-end American television and show the American method actors how it’s done – sometimes, even, at the beginning of their screen careers, at a competitively low wage.Stewart was one of the thoroughbreds of the Royal Shakespeare Company’s 1970s stage generation who had also had classy small screen roles, such as his intimidating Sejanus in I, Claudius opposite Derek Jacobi. But he effected a...