In recent years, in parallel with the rising interest for the history of international law and the evolving of a separate discipline of “Comparative International Law”, interest for national international law traditions—and in particular for European international law traditions—has continuously grown. This process raises a series of questions, in particular whether the assumption of the existence of such traditions is compatible at all with the very nature of international law, about the meaning of “Europeanness” and about the end of such a comparative endeavour. The present book collects a series of analyses in this field undertaken by renowned international lawyers. Of course, such a project cannot claim to give definite, encompassing answers, but it can aim at providing a better understanding of why international law is as it is, evidence what may be at the roots of so many misunderstandings in the international law dialogue between nations and academics and also, on a more positive note, show to what extent a common language has evolved and what the different national contributions were to these achievements.For the time being, studies of such a kind cannot be but electrical. Nonetheless, the hope is that they might contribute to a broader understanding of international law, offer a better comprehension in the discussion between international lawyers and perhaps build the basis for further studies in this area. This introductory chapter describes the research project as a whole, offers some methodological considerations and provides a short glimpse into the chapters of this book.