In January 1938, Benny Goodman took command of Carnegie Hall on a blustery New York City evening and for two hours his band tore through the history of jazz in a performance that came to define the entire Swing Era. Goodman played Carnegie Hall at the top of his jazz game leading his crack band—including Gene Krupa on drums and Harry James on trumpet—through new, original arrangements by Fletcher Henderson. Compounding the historic nature of the highly publicized jazz concert, Goodman welcomed onto the stage members of Duke Ellington’s band to join in on what would be the first major jazz performance by an integrated band. With its sprit of inclusion as well as its emphasis on the historical contours of the first decades of jazz, Goodman’s Carnegie Hall concert represented the apex of jazz music’s acceptance as the most popular form of American musical expression. In addition, Goodman’s concert coincided with the resurgence of the record industry, hit hard by the Great Depression. By the late 1930s, millions of Americans purchased swing records and tuned into jazz radio programs, including Goodman’s own show, which averaged two million listeners during that period. And yet, only forty years separated this major popular triumph and the very origins of jazz music. Between 1900 and 1945, American musical culture changed dramatically; new sounds via new technologies came to define the national experience. At the same time, there were massive demographic shifts as black southerners moved to the Midwest and North, and urban culture eclipsed rural life as the norm. America in 1900 was mainly a rural and disconnected nation, defined by regional identities where cultural forms were transmitted through live performances. By the end of World War II, however, a definable national musical culture had emerged, as radio came to link Americans across time and space. Regional cultures blurred as a national culture emerged via radio transmissions, motion picture releases, and phonograph records. The turbulent decade of the 1920s sat at the center of this musical and cultural transformation as American life underwent dramatic changes in the first decades of the 20th century.