Book excerpt: Energy security, at the heart of energy policy, has become central to the dynamics of international relations. Political turmoil has overwhelmed many oil and gas producing countries, forcing them to adapt their national energy policies according to this continuous change. Specifically, because of the wars and instability in the Middle East and the Ukrainian crisis, global energy security is no longer guaranteed. One of the foremost experts on the energy industry, Daniel Yergin, identifies energy security as “the availability of sufficient supplies at affordable prices.” He also comments that every country interprets the definition of energy security with its own dynamics. In practice, the definition of energy security is polysemic and the topic of energy security is being explored daily, under the lens of numerous new studies, by scholars, energy experts, government officials, activists, and journalists.