In the 1955 movie musical, High Society, Bing Crosby presents perhaps the swingiest definition of a historic district in the song “Now You Has Jazz.” Crosby introduces Louis Armstrong and his band members individually as a “collection of virtuosos, ’bout the greatest in the land.” As the whole band begins to play, Crosby leans back against the piano and declares that “le tout ensemble” is “positively therapeutic.”1 Crosby’s characterization of a collection of significant individual artists, supporting a keystone of one very important maestro, offers a fine analogy for the concept of historic districts within historic preservation.