Unless you're a 78 collector, the name Nathaniel Shilkret probably means absolutely nothing to you. But there was a time Shilkret was one of the most popular and recognized composer/band leaders in the early days of recording. He began with RCA Victor in 1915 and was one of the first bandleaders recording almost exclusively for that label from the earliest days of acoustic recording all through the 1930's.
Although primarily known as a bandleader, Shilkret also composed a goodly amount of serious music, including one Trombone Concerto originally written for Tommy Dorsey who commissioned it in 1943.
Ironically, there doesn't seem to be any record of Dorsey actually performing this piece. And after several tries (which never happened because of timing or agreements) and several revisions, it was set down and pretty much forgotten about until a recent re-discovery of this piece brought about new interest in it.
I don't think this particular recording has ever been available commercially so you probably get to hear it here first, roughly two months after it received its World Premier in New York.