The relationship between energy and security has been receiving increasing attention over the last few years. Energy literally drives the global economy. Societies rely on it for everything from advanced medical equipment to heating, cooling, and irrigation. Whether it derives from advanced nuclear reactors in developed nations or simple woodstoves in the developing world, energy is recognized as vital to human welfare. It influences our economic, political, and social policies. Possessing or not possessing sufficient energy determines a state's political and economic power. Competition for energy has been, is, and will be a source of conflict. The choices nation-states make when it comes to energy will have a profound bearing on a wide range of security concerns, from nuclear proliferation to climate change.