Synopsis Energy has played a unique role in the development of economy and history of modern times. No other resource has been so critical in shaping destiny of nations, the development of military and global trade strategies and relationship among countries. No other resource has offered such great promises for improving the well being of entire nations, many of these promises have sadly remain unrealized and which often have turned into curses looming over their future. No other resource had such a huge impact on the geography of our world and the way our society are behaved and organized. Energy fulfils an endless list of expectations that are necessary for our modern way of life to continue for another day. All this depends on energy; be it electricity, natural gas, gasoline or diesel fuel, petrol or from renewable sources. Energy demand is increasing and its conservation has become absolute necessary. There is gradual depletion of Earth's finite energy resource and problem of potential global climate change. This encyclopaedic set examines the principal issue concerning energy sector. These contemporary ideas include concepts of energy economics, the regulation and policy framework, the conservation issues, the global energy trade and finally the idea of achieving energy security.