It is hard to overstate the importance of energy. 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 is a key determinant of a state's political and economic power. Competition for energy has been, is, and will be a source of conflict. And the choices we make when it comes to energy will have a profound bearing on a wide range of security concerns, from nuclear proliferation to climate change. The joint Triangle Institute for Security Studies (TISS)/North Carolina State University (NCSU)/Strategic Studies Institute (SSI) conference on the "Energy and Security Nexus," which was held on March 3-4, 2011, addressed many of these issues. To place the remarks made at this conference within a clearer context, a few terms and concepts need to be discussed. To provide a further framework for the reader, these definitions will be followed by a brief threat assessment, a cost-benefit analysis of different energy technologies seen from a security perspective, and an overview of the chief findings of the conference.