This introduction presents an overview of the key concepts discussed in the subsequent chapters of this book. The book shows policymakers how politicians and regulators have responded to the shale boom in the real world, confronted by the constraints imposed by political institutions. It considers the economic foundations of the American shale boom. The book analyzes the regulatory institutions governing fracturing. It focuses on the diversity of responses in polycentric systems of governance. The book reviews what the economics literature says about the extent to which the benefits of the US shale gas revolution exceed its costs. It considers a broad set of benefits and costs of the shale boom, including economic growth, employment in the shale gas sector, employment in related sectors, and a variety of external costs, including those related to health and environment. The book describes the response to fracking in shale-rich countries.