The question raised by European Private Law is now no more a question of existence but of boundaries. The question of the boundaries refers not only to the territorial and material scope of EPL but also to the increasing diversification of the methods used to harmonise and coordinate EPL rules (concept of “methodological boundary”).European Private Law stands at the crossroads of several processes of legal integration. A first process of integration results from the development of the EU legal order, a second one from the binding character of the interpretation of the ECHR. One can also add to these the impact of the harmonizing activity of international institutions like the Hague Conference on Private International Law and UNIDROIT since the instruments adopted by these institutions now take into account the phenomena of regional integration in their drafting.The papers collected in this book analyse how each of these processes exert an influence on the definition of EPL’s territorial and material boundaries.A first group of contributions deals with methodological aspects of the question whereas a second group adopts a disciplinary approach. From the confrontation of both perspectives, it appears that: 1) the level of Europeanisation is uneven from one legal field to another so that the question of the boundaries of EPL necessarily entails a discussion of the objectives, obstacles and limits to the Europeanisation of law, 2) when becoming European, Private Law goes through a transformation of its modes of intervention and develops a regulatory dimension which questions the distinction between public and private law.