This essay deals with needs and problems of the initiatives aiming at a legal integration in Europe. In the first part of the paper (II-IV) the need of a wider and deeper knowledge of legal data is stressed by the author through the comparison of (overt) methods and (hidden) implications pursued by research-oriented enterprises — such as "The Common Core Project' or the 'European Case-books Project' - on the one hand, and the initiatives whose goal is the creation of rules — such as the UNIDROIT Principles or the 'Lando Commission' - on the other. The second part of the article (V.-VI.) highlights the reality of multi-level legal systems as one of the most important problems any integrative enterprise has to face. The author's ranking and analysis of the legal layers at work in the European societies — eg: different levels of local customary rules, 'national' rules, tansnational business rules, EU rules — aims at making out, at least, how fully aware a Code or any other authoritative regulation has to be about the kind and level of integration to pursue.
European Review of Private Law