A Broadway classic, a call to action, and an incredibly malleable popular song, "Ol' Man River" is not your typical musical theater standard. Written by Jerome Kern and Oscar Hammerstein II in the 1920s for Show Boat, "Ol Man River" perfectly blends two seemingly incongruous traits-the gravity of a Negro spiritual and the crowd-pleasing power of a Broadway anthem. Inspired by the voice of African American singer Paul Robeson, who adopted the tune...