Iola Leroy; or, Shadows uplifted, by Frances E. W. Harper.

This novel stands out as a significant achievement in African-American literature prior to the 20th century, garnering acclaim for its storytelling and cultural impact. It explores themes of identity, resilience, and the African-American experience, making it a pivotal work in understanding the historical context of its time. Its popularity reflects both its literary merit and its role in shaping the narrative of African-American voices in literature.