The classic conception of energy security addresses the relative supply and safety of energy fuels and services. Yet the past three decades have seen both the emergence of new energy security threats, such as climate change, and new conceptions of energy security, such as definitions which focus on social stewardship, affordability, or innovation of energy research and development. The articles collated in this new 6-volume major work chart these significant developments, and place them in a wider context through a comprehensive and illuminating introductory chapter, written by editor Benjamin K. Sovacool and energy security expert Scott V. Valentine. Divided thematically, the volumes cover the following topics: Volume One: Definitions, and Concepts Volume Two: Fuels and Technologies of Energy Security Volume Three: Economic, Political, and Environmental Dimensions of Energy Security Volume Four: Regional Perspectives of Energy Security Volume Five: National Perspectives of Energy Security Volume Six: Indices and Measures of Energy Security Progress