A favor can bind more tightly than a contract. Across villages, ports, prisons, borderlands, and occupied cities, exchange often depended on personal credit, reciprocal duty, and illicit access. This history traces the moral and political worlds surrounding unofficial commerce, showing how authorities alternately tolerated, taxed, criminalized, or exploited it. By focusing on relationships rather than prices alone, it reveals how invisible economies redistributed risk and created parallel forms of authority beneath formal institutions.