This volume presents the outcome of the research programme carried out by the network of European international lawyers on the theme of international norms and legal barriers. The research was carried out on the basis of a single questionnaire, which provided the outline of a common workplan, to which each of the contributors has adhered. Detailed comparisons of national practices can now be made, relating in particular to international treaties, acts of international organizations and of the European Community, and to unwritten international law.
