This volume presents the papers of an international group of academic experts treating the following core issues: Can co-operation between antitrust authorities replace an international antitrust agreement by generating common antitrust standards?; How do diverging domestic cultures and diverging concepts of competition influence our conception of international antitrust law?; Does co-operation work in specific areas, such as merger cases?; Does international antitrust law have to deal with new areas of concern, such as Internet-related problems and co-operation between undertakings?; To address most effectively international restraints on competition, should we rely more on national, supranational or international antitrust standards and enforcement or must we combine these approaches?; What can we learn from our experience in multilevel jurisdictions like the United States and the European Union?; And do we need agreement on harmonized substantive law standards, or would it be more effective to rely on common rules of enforcement?