Over the past several decades, the share of U.S. workers holding an occupational license has grown sharply. When designed and implemented carefully, licensing can offer important health and safety protections to consumers, as well as benefits to workers. However, the current licensing regime in the United States also creates substantial costs, and often the requirements for obtaining a license are not in sync with the skills needed for the job. There is evidence that licensing requirements raise the price of goods and services, restrict employment opportunities, and make it more difficult for workers to take their skills across State lines. Too often, policymakers do not carefully weigh these costs and benefits when making decisions about whether or how to regulate a profession through licensing. In some cases, alternative forms of occupational regulation, such as State certification, may offer a better balance between consumer protections and flexibility for workers. This book outlines the growth of licensing over the past several decades, its costs and benefits, and its impacts on workers and work arrangements. The book recommends several best practices to ensure that licensing protects consumers without placing unnecessary restrictions on employment, innovation, or access to important goods and services.