Rules are no longer merely made by states, but increasingly by international organizations and other international bodies. At the same time these rules do impact the daily life of citizens and companies as it has become increasingly difficult to draw dividing lines between international, EU and domestic law. This book introduces the notion of 'multilevel regulation' as a way to study these normative processes and the interplay between different legal orders. It indicates that many rules in such areas as trade, financial cooperation, food safety, pharmaceuticals, security, terrorism, civil aviation, environmental protection or the internet find their origin in international cooperation.Apart from mapping multilevel regulation on the basis of a number of case studies, the book analyses its consequences in relation to forms of legal protection and legitimacy. In that respect it proposes an agenda for research to study how to cope with multilevel regulation. This book offers valuable resources for researchers involved in studying the interplay between international, European and domestic law. For practitioners it offers background information on the ways in which many international rules come into being.