Capitalism by Gaslight was a 2012 exhibition at the Library Company of Philadelphia. Taking its title from a 19th-century literary genre that exposed the darker side of American life, Capitalism by Gaslight introduces us to many of these shadowy entrepreneurs. At its heart the exhibition attempts to neither romanticize nor condemn, but to present the commerce of extra-legal businesspeople in more nuanced yet concrete ways. Although these transactions occurred most expediently in secluded back alleys and basement hideouts, many conmen benefited from the air of legitimacy given to schemes pulled off in broad daylight. And although entrepreneurs working in gray and black markets were excoriated by prominent businessmen, reformers, and authorities, they often had intimate ties to legitimate commercial networks and enjoyed the fruits of their very critics’ patronage. Possessing an entrepreneurial spirit, many underworld operators closely resembled respected businessmen. Perhaps most surprisingly, these illegal forms of commerce were integral to the success of the larger American economy and continue in varied forms today.