WHAT’S IN THIS VIDEO: Why does one piece of music become popular and find a place in the repertoire and another doesn’t? It’s not a matter of quality. Music goes in and out of fashion. Composers go in and out of fashion. At one time, Bach’s music was forgotten. Gershwin wrote one of the most popular pieces in American music with his Rhapsody in Blue. His Second Rhapsody, which had many advantages in being introduced to the public, was forgotten. We’ve asked conductors, a composer, a critic, an artist manager, a PR maven and a singer if they know the secret sauce of popularity.