Book excerpt: What do Robert Johnson, Duke Ellington, Marvin Gaye, Madonna, and 2 Live Crew have in common? Each of their respective music forms--blues, jazz, soul, rock, and rap--contains varying degrees of religious essence and theological meaning. By examining the religious roots and historical circumstances of popular music, scholars and essayists--including Cornel West, Michael Eric Dyson, and Andrew Greeley--delve into the religious imagination of the American populace through an analysis of popular music. In sections devoted to popular music forms once identified as "the devil’s music," religious concepts and controversies are discussed: music as "soul therapy," the darker side of pop, secular angst, and sacred aspiration.