This multidisciplinary overview of European integration examines the theories of European integration as well as related theoretical and empirical works in political science, sociology, and economics. Contents: Preface; Hans J. Michelmann and Panayotis Soldatos, The Hard Core of European Integration Theories and Approaches: A Multivariate Track of Variable Geometry; David Mutimer, Theories of Political Integration; Werner J. Feld, Sociological Theories of European Integration; Alfred Tovias, A Survey of the Theory of Economic Integration; Alex Easson, Integration Through Law: The Court of Justice and the Achievement of the Single Market and the European Union; Pierre-Henri Laurent, Reappraising the Origins of European Integration.