The best-selling masterpiece shows how two forms of song - the spirituals and the blues - helped sustain slaves and their children in the midst of "a powerful lot of tribulation." The spirituals speak about the rupture of black lives, about a people in the land of bondage. The blues are secular spirituals, telling about love and sex and black life and the gut capacity to survive. Both musical forms undercut the dominant society, strengthening the black community in the face of oppression.