This comprehensive book on the European energy transition has been written by more than 40 European leading energy- and climate experts. It reflects on the latest policy developments, as such as the Clean Energy for All Europeans Package, the Green Deal and the Climate Law. The energy transition is Europe’s flagship projects. It needs to provide sound answers to the climate and sustainability-, security of supply- and competitiveness imperatives. The energy transition corresponds to a large scale economic and cultural change. It encompasses sector coupling- linking up sectors that have ignored each other previously, like mobility and power. What is the meaning of digitalization, and how to face cybersecurity risks? Can Europe deliver a 50-55% decrease in Greenhouse Gas Emissions, as is the agenda of the new von der Leyen Commission? This 2nd edition is not only updated, but also augmented with three new chapters : the first focusses on a European cross border carbon adjustment proposal (by Genevieve Pons, Pascal Lamy and Pierre Leturcq). This mechanism is a center piece in the European Green Deal and as such debated intensively. Two other chapters present the value-add and next steps for European network codes and guidelines (Alexander Dusolt, Leonardo Meeus). The book analyses the factors driving change: where are we on climate and sustainability, competitiveness and market, and security of supply? It presents the actors: what genesis of and what contemporary institutions for European energy policy, how is energy addressed by the national and by the European; what about the active customer paradigm and the many startups and business models changing, as well as NGOs? It investigates sectors: power, gas, mobility and the powerful push from digitalization.