Samuel Barber is one of the most important American composers in the twentieth century. He wrote 103 solo songs. Among these works, Knoxville: Summer of 1915, op. 24 is unique because its scale is larger than other vocal works and because it is the only piece Barber wrote for soprano and orchestra. Since the premier in 1948, this masterwork is considered the most ¡§American¡¨ piece of Barber¡¦s works, for that he successfully sketches the atmosphere described in the lyrics, that is, American country life during the 1910s. The main issue of this short thesis is to reveal reasons that make the work well-known for its ¡§most American¡¨ nature. The musical education of the composer, the short biography of the poet, and the compositional background of Knoxville: Summer of 1915, op. 24 are mentioned. Through the analyses of lyrics, tempo and melody, the discussion focuses on how Barber translates the picture of American country life during the 1910s into musical notes.