Few American artists in any medium have enjoyed the international and lasting cultural impact of Duke Ellington. From jazz standards such as "Mood Indigo" and "Don't Get Around Much Anymore," to his longer, more orchestral suites, to his leadership of the stellar big band he toured and performed with for decades after most big bands folded, Ellington represented a singular, pathbreaking force in music over the course of a half-century. At the same time, as one of the most prominent black public figures in history, Ellington demonstrated leadership on questions of civil rights, equality,...