Songs of Zion focuses on the African Methodist Episcopal Church, black America's oldest and largest independent church. Campbell charts the origins and evolution of African American independent churches, arguing that the very act of becoming Christian forced black Americans to reflect on their relationship to their ancestral continent. The book then turns to South Africa, examining the AME Church's entrance and evolution in a series of specific African contexts. The final third of the book is devoted to what Campbell calls "middle passages," to the careers of men and women who moved between South Africa and the United States in the nineteenth and twentieth centuries. Throughout the book, Campbell focuses on the comparisons that Africans and African Americans themselves drew between their situations, arguing that the transatlantic encounter enabled both groups to understand and act upon their worlds in new ways.