A man of untiring energy and humor, Nicolas Slonimsky has led a long and accomplished musical life, and today in his nineties he is a vital presence in American music. In 1985, an extensive New Yorker profile described him as "a man of countless daffy stunts and almost as many authentic achievements." Indeed, Slonimsky pursued four distinct careers, each with its own degree of success: as a pianist, as a composer, as an pioneering conductor who championed...