Book excerpt: "To the economist and ballet enthusiast John Maynard Keynes he was potentially the most brilliant man he'd ever met; to Dame Ninette de Valois he was the greatest ballet conductor and advisor this country has ever had; to the composer Denis ApIvor he was the greatest, mostr lovable, and most entertaining personality of the musical world; whilst to the dance critic Clement Crisp he was quite simply a musician of genius. Yet sixty years after his ... death Constant Lambert is little known today. As a composer he is remembered for his jazz-inspired The Rio Grande but little more, and for a man who ... devoted the graeter part of his life to the establishment of English ballet his work is largely unrecognized today. [This book] looks not only at his music but at his journalism, his talks for the BBC, his championing of jazz (in particular, Duke Ellington), and, more privately - his longstanding affair with Margot Fonteyn. ..."--Book jacket.