Steve Martin was never interested in finding just one niche and remaining there for his entire life, as evidenced by his career evolution from TV writer to goofy stand-up comic to A-List star of offbeat comedies, family fare, dramas and musicals. His early, rock-star like fame as a comedian influenced a whole generation of performers with its experimental, no- punch-line style that sent-up vaudeville as much as it borrowed from his studies as a philosophy major....