The expatriate American experimentalist composer Conlon Nancarrow is increasingly recognised as having one of the most innovative musical minds of this century. His music, almost all written for player piano, is the most rhythmically complex ever written, couched in intricate contrapuntal systems using up to twelve different tempos at the same time. Yet despite its complexity, Nancarrow's music drew its early influences from the jazz pianism of Art Tatum and Earl Hines and from the rhythms of Indian music; Nancarrow's whirlwinds of notes are joyously physical in their energy. Composed in almost complete isolation from 1940, this music has achieved international fame only in the last few years. Born in 1912, the son of the mayor of Texarkana, Nancarrow fought in the Lincoln Brigade, then fled America to Mexico City to avoid being hounded for his former Communist affiliations. The author travelled to Mexico City to research Nancarrow's music and to discuss it with him. He analyses sixty-five works, virtually the composer's complete output, and includes a biographical chapter containing much information never before published.