The European legal order is currently the fundamental framework within which the tax relationship should be determined and regulated and is going to become the general point of reference of the taxation power. Therefore, the analysis of principles and institutions of European tax law can permit the formation of a solid background not only about the tax discipline, but moreover about the dialectic of fundamental values of the social and civil life in the European territories. The book is aimed to provide an overall and systematic overview of the main topics of the European tax law. The sequence of arguments follows an institutional logic, and namely it respects the progression usually addressed in the academic tradition of the tax law. Particularly, the general framework of the EU institutions is outlined, addressing a special attention to the set of regulations regarding taxation, with reference to the stage of formation of EU rules and to the potential contrast with the national legal systems. A special attention is given over to the general principles emerging from the European Treaties which typically involve the taxation system. This bring to a detailed examination of the fiscal importance of European freedoms, the principle of tax non-discrimination, the balance between national interest and EU values, the tax harmonization, the State aids and other general principles applicable in the tax jurisdiction. Finally, it is proposed an overall judgement about the development of the European integration process, with particular regard to the nexus between taxation power and sovereignty and to the values of taxation matters, in order to highlight the possible and desirable next stages of the evolution of "European tax law".