The energy transformation poses unprecedented challenges for national legal systems. Without systematic comparative law as a basis for learning from each other, national legislators will not be able to overcome these challenges. Against this background, the present work presents a comparative law analysis of the energy transformation in Europe in general and with a special focus on the law of renewable energies. The legal systems of Denmark, Germany, France, Italy, Poland and Sweden were analysed for the area of the European Union as well as the United Kingdom as a former member of the EU and important pioneer of energy transition and climate law. With contributions by Prof. Helle Tegner Anker | Agnieszka Ason | Prof. Dr. Michael Fehling, LL.M. (Berkeley) | Asso. Prof. Louis de Fontenelle | Prof. Fabrizio Fracchia | Prof. Bent Ole Gram Mortensen | Dr. Aleksandra Knap | Prof. Marie Lamoureux | Asso. Prof. Melina Malafry | Ass. Prof. Chiara Mari | PD Dr. Till Markus, LL.M. | Kate McKenzie, PhD | Prof. Dr. Michael A. Mehling, LL.M. | Dr. Bartłomiej Nowak | Asso. Prof. Sirja-Leena Penttinen | Prof. Dr. Johann-Christian Pielow | Prof. Dr. Michael Rodi, M.A. | Prof. Dr. Johannes Saurer, LL.M. (Yale) | Prof. Kim Talus