Many writers have documented the abuses of the Belgian king Leopold II, who ruled the Congo Free State as a private fiefdom around the turn of the twentieth century. In search of ivory and rubber, Leopold’s agents committed unspeakable atrocities and violence that persisted even after Belgium nationalized the Congo Free State in 1908 to make it a more conventional colony. Harms’s deeply rewarding account of this history breaks new ground by broadening the context of Leopold’s depredations. His book places Leopold’s excesses alongside two other deeply exploitative state-building ventures in central Africa: France’s pillaging of its own neighboring Congo colony and the handiwork of the slave and ivory trader Tippu Tib, who operated on behalf of the sultan of Zanzibar and carved out an Arab zone of influence in the eastern half of the vast Congo River basin. Harms’s focus on economic and material factors reveals how the global demand for ivory and rubber shaped all three ventures.