Harlan Leonard first showed up on traditional jazz radar as a member of Bennie Moten's Kansas City Orchestra. He joined in 1923 and served as a vertebra in the backbone of the Moten reed section until 1931. Teaming up with another Moten veteran, Leonard worked with Thamon Hayes' Skyrockets, helping to steer this band until it too dissolved in 1937. Leonard formed his own Rockets in 1938. In 1940 they appeared at the Golden Gate Ballroom in New York, recorded about 23 sides for Bluebird, toured all over the continental United States, and finally disbanded in 1945 while working in California. This band contained a lot of young talent from Kansas City. Hearing all of their records in one package is a gas. Swing had matured. It was obviously ready to lunge forward into big-band modernity…