Due to the exploitation of international reservoirs, natural energy sources have become rare, disputed among States and therefore strategic. The reliance on these resources is linked to energy security and dependence in both terms of energy imports or exports. Furthermore, the access and reallocation of energy flows entail an alteration of the balance of power among States as well as the raise of national energy security strategies and debates. The aim of this volume is to analyze the evolution of energy relations between the European Union and the Russian Federation from a state of pure Dependence to the establishment of a balanced Interdependence, underling also the challenges facing the EU in terms of dependence and diversifications in the framework or the EU-Russian energy cooperation.