African American literature is the boy of literature produced in the United States by writers of African descent. The genre traces its origins to the works of such late 18th century writers as Phillis Wheatley and Olaudah Equiano, reaching early high points with slave narratives and the Harlem Renaissance, and continuing today with authors such as Toni Morrison, Maya Angelou and Walter Mosley being ranked among the top writers in the United States. Among the themes and issues explored in African American literature are the role of African Americans within the larger American society, African-American culture, racism, slavery, and equality. African American writing has also tended to incorporate within itself oral forms such as spirituals, sermons, gospel music, blues and rap.