This is a long-term study of the Bobangi people of the upper Congo River. The Bobangi were riverine inhabitants who, prior to the opening of the Atlantic world, traded with their agriculturalist and foraging neighbours. The Bobangi developed mechanisms that served them well once the Atlantic trade started, including long-distance networks of exchange, flexible currency units, and large numbers of canoes. These vessels were stocked with textiles, metals, palm oil, and slaves which were exported to the coast. For a time, the Bobangi world became a "river of wealth," stimulated by the Atlantic trade. This system, however, was destabilized over time as the demand for enslaved people reached a fever pitch in the eighteenth century. In the early centuries of commerce, many Bobangi communities were able to balance external and internal patterns of supply and demand across a stretch of some 1,000 miles of waterways. Ultimately, however, demographic collapse, ruthless power struggles, and over-reliance on coastal commerce turned the region into a "river of sorrow."