Native Scotsman Craig Ferguson made a splash in front of some of America’s biggest TV audiences as the gleefully malign English boss Mr. Wick on the ABC hit “The Drew Carey Show” (1995-2004), but found his true voice, quite literally, before much smaller late-night audiences, playing himself to a fault. A dark horse selection by CBS and its “Late Show” (1993- ) mainstay David Letterman to host the latter’s lead-out “The Late Late Show” (CBS, 1996- ) Ferguson has carved out a unique cultural space of slashing wit, unscripted monologues and disarming personal candor to where, according to his native land’s Scotland on Sunday newspaper, “[h]e now rivals Sir Sean Connery and Ewan McGregor as the best-known Scot in the US....