This work investigates the artistic genius and complex personality of Duke Ellington through the lens of his long-term musical evolution. Whitney Balliett, a long-time jazz critic for The New Yorker, utilizes his extensive experience observing the jazz scene to construct a portrait of Ellington. The book argues that Ellington’s contributions to American music transcend simple composition, positioning him as a central figure in the development of 20th-century orchestral jazz. Balliett relies on a combination of personal interviews, concert observations, and critical analysis of Ellington's recorded output to support his assessment.

Critics and jazz historians frequently cite this work as a vital, observational account of Ellington's later career. Readers often note the accessible yet insightful prose style that characterizes Balliett's writing on the jazz genre.