George Gershwin grew up in New York City and he first made his living playing popular music on the piano in “Tin Pan Alley,” the music publishing district of New York. It was there that he developed a strong feel for the popular music of the time that served as a basis for the popular songs that he composed. In addition to his love of popular songs, he enjoyed jazz and believed that jazz was the primary source of truly American folk music. Jazz had, prior to Gershwin’s time, been performed by small jazz bands and soloists, but Gershwin believed that jazz could serve as the basis for serious symphonic works. Gershwin became the link between jazz and serious classical music with such works as his jazz concerto Rhapsody in Blue and the jazz-inspired orchestral An American in Paris.
from Longman Introductory for TOEFL