This volume examines energy security in a privatized, liberalized, and increasingly global energy market, in which the concept of sustainability has developed together with a higher awareness of environmental issues, but where the potential for supply disruptions, price fluctuation, and threats to infrastructure safety must also be considered. Part I commences with an essential introductory chapter which defines energy security and sets forth the key issues and themes of the book. There then follow several cross-cutting chapters which include sceptical analysis of energy security claims from an environmental perspective and a broader geopolitical analysis of energy security. Part II examines a wide variety of international, regional, and national approaches to energy security issues. Energy security concerns differ considerably from country to country, however most of the chapters examiming particular nations provide an economic and historical context of their energy security concerns, followed by a detailed analysis of the legal provisions relating to each of the main energy sectors (oil, gas, coal, electricity, nuclear, and renewable energies). This entails examination of regulation, organization, and planning for security and other purposes. In a number of cases, energy security law is shaped by other factors such as market liberalization, environmental protection, and competition policy. Part III comprises two final chapters, the first contrasting the various national and regional approaches and analysing cross-cutting issues, whilst the concluding chapter forecasts future trends in the legal regulation of energy security.