Back in the late '90s, I was part of a long, late night grad school discussion, purely theoretical, wherein we debated who might be the greatest (or most important) instrumental musician of the 20th century. We argued in terms of genres (classical, jazz, pop, etc), in terms of social and political importance, and in terms of historical importance. To the surprise of all of us (myself decidedly included), by the end of the evening, we all agreed it was Benny Goodman.
From his dominance of the pop charts in the '30s and '40s, to his virtuosic jazz playing (which pushed soloists' boundaries across the artform), to his racially integrated quartet and sextet (which blazed the way for Jackie Robinson in baseball, as Lionel Hampton pointed out), to his commissioning of repertoire pieces such as the Copland Concerto and Bartok's Contrasts, there is really no parallel for his career.
Happy birthday, Benny Goodman, born on this day in 1909!