This book dissects the causes and consequences of state licensing of businesses, services and occupations in the USA. Licensure is the granting of a permit from an authority to own or use something, to provide a particular service, or to carry out a trade. By and large, states rule industry licensing. Yet state differences in licensing requirements are far from idiosyncratic. In short, there is a political side to state licensing that has largely gone uncharted. This book rectifies this omission. Adopting a multidisciplinary approach, it illuminates the significance of politics to the study of state licensing by establishing the relevance of legislator motives and preferences. Presenting economic and political data for US states, including extensive data on campaign contributions, lobbying, and state licensing statutes, it demonstrates that state licensing requirements are driven by political motivations rather than protecting the public interest. It will appeal to scholars and students of public policy, public administrators, industry lobbyists, economists and political scientists who are interested in understanding the motivations behind regulations.