In 1862 the New York Times reported that nearly 80 percent of American currency in circulation was counterfeit. In New York and Philadelphia outlaw engravers worked by day for the banks that issued real bank notes and by night supplied counterfeits to an underground industry. By the end of the 1860s counterfeit production and distribution networks had spread nationwide.

The federal government was compelled to respond to this growing illegal enterprise, which represented a threat to both the national economy and the federal government's authority to control the currency. In 1865 it created the Secret Service - an agency that over the next forty years, would eradicate counterfeiting as a major urban crime.

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Illegal Tender chronicles one of the most successful law enforcement campaigns ever conducted against the American underworld. With colorful vignettes of criminals and their gambits, David R. Johnson explores the evolution of counterfeiting as a peculiarly urban crime, detailing its markets, advertising, and distribution networks - as well as such schemes as the "green-goods game," which netted some outfits $40,000 a month in profit.

He examines the initial mission of the Service, its crime-detecting strategies, and its role in the growth of federalism and state building in the nineteenth century. Created by the Treasury Department despite long-standing and fierce opposition to the expansion of centralized power in American society, the Service gradually superseded the efforts of both local police and federal marshals, virtually eliminating counterfeiting operations throughout the nation by the end of the century.