The European Union has set the objective to achieve a secure, sustainable and competitive energy policy. The development of a European energy policy is constantly emphasised in the declarations of political leaders. This book provides an assessment of the legal feasibility of a EU energy policy by looking into the sensitive areas of industrial restructuring, institutional reform and security of supply. The famous Endesa saga offers a paradigmatic case about the tensions between energy champions and energy markets. The persistence of monopolistic structures despite the liberalisation process requires the reinforcement of regulatory authorities, both at national and EU levels. Furthermore, while security of energy supply is in principle a responsibility of Member States, who often use that responsibility as a pretext to promote national champions, it also has a European dimension in terms of external dependence and internal solidarity. The absence of a specific legal basis on energy in the treaties did not prevent the EU from developing a European energy policy. A more coherent approach to energy policy should be expected with the new legal basis on energy in the Lisbon Treaty.