Whee, was that a cunning, elegant man!"" So said Dizzy Gillespie of the Duke, and ""cunning"" is right--cunning enough to reveal little of himself in Music Is My Mistress and cunning enough to have left any biographer the near-impossible task of wrestling with the public persona--indefatigable performer, fancy dresser, swell talker--that totally obscured whatever private man there was. Jewell makes only an occasional probe into those privacies (the superstitious theist, the monogamous womanizer, the White House honoree who declared, ""There is no place I would rather be tonight, except in my mother's arms""), contented to tag along chronologically, concentrating on the music. From Washington to Harlem to Europe to the 1956 ""renaissance"" at Newport, from five-piece combo to lush big band to Sacred Concerts, anecdotes and quoted recollections blend reasonably well with Jewell's appreciations of Duke's (and alter ego Billy ""Swee' Pea"" Strayhorn's) compositions. The ceaseless, Podunk-to-Paris touring and the comings and goings of distinctive band soloists come across better than Duke's creative development, and London engagements and swank fans (Jewell is a Sunday Times critic) receive far more attention than comparable New York appearances and theater or film scores. Little-known and ill-regarded works (the programme-y ""Sweet Thursday,"" the ""Single Petal"" piano solo dedicated to devotee Elizabeth II) are highlighted, leaving some of the standard repertoire disenfranchised, and Jewell's mix of Britishisms with jive makes one almost as uneasy as does his taste for hyperbole: "". . . in quantitative terms there can indeed never have been another musician of any description to approach him in any century."" Still, most of those gaps in Music Is My Mistress are filled, Jewell provides a convenient chronology and a decent discography, and his first-hand contacts with the aging Duke enliven a respectable attempt at capturing that elusive, sophisticated gentleman.