by Richard S. GinellFor someone of Steve Allen's versatility and staggering capacity for work, jazz occupies a small yet significant portion of his biography. Yet despite his crowded agenda, Allen can still spin out facile, competent, bop-and-cocktail-flavored piano in fast jazz company -- nothing particularly original but always pleasurable to hear. He started to play the piano while a child - his parents were traveling vaudeville performers -- but the keyboard soon had to take a backseat to his media career, first on radio and then on television. Best-known as a comedian and the first host of the American TV institution, the Tonight Show (1954-57), Allen frequently played piano and sang on his shows and used them as a forum to present guests from the jazz world. He also played the lead role in the film The Benny Goodman Story in 1955, produced the TV series Jazz Scene USA in 1962, and narrated a history of jazz on records The Jazz S...