harmonies every few beats, making it closer to "art music," less catchy and more difficult to execute.

Also, the blues always functioned like folk music; anyone who really wants to can sing and play the blues. And the blues vocabulary has never changed much. Whether it's Bessie Smith, Robert Johnson, Ethel Waters, Skip James or Muddy Waters, it's still the blues.

But it took Louis Armstrong, James P. Johnson, Duke Ellington, Count Basie, and especially Billie Holiday to synthesize the best of ragtime and blues and distill it into jazz. But that is a story for another day.