Already by the 1820s, the national capital of Washington, D.C. had emerged as a significant depot in the increasingly professionalized domestic slave trade. The introduction sketches the history of slave dealing in the capital, William H. Williams’ emergence on to the slave-trading scene there, and the broad contours of how the slave trade functioned, often depositing its victims for sale in New Orleans, Louisiana. It argues that the story of William H. Williams and his one shipment of convict slaves purchased in 1840 provides a snapshot of the antebellum era socially, economically, politically, and legally.