The Crime of the Congo by Arthur Conan Doyle

Doyle documents the atrocities committed in the Congo Free State, the personal possession of Leopold II of Belgium. Thousands of native Africans were forced to labor on rubber plantations for the benefit of their colonial overlords. The abuses of the Congo Free State, and worldwide denunciations when they came to light, were instrumental in the Belgian government assuming responsibility of the territory and renaming it the Belgian Congo.