Stephen Foster is one of the most enduring figures in 19th century American music -- a status borne out by the fact that he and his music are still being discussed in the 21st century. In an era when even Charles K. Harris, whose "After the Ball" sold millions of copies of sheet music at the end of the 19th century and got a further boost from its inclusion in the musical Show Boat, is scarcely remembered at all, Stephen Foster still looms astonishingly large over American popular music and popular culture. His songs, including "Oh! Susanna," "Jeanie with the Light Brown Hair,...