There is an increasing consensus among students of European integration that theories of international relations (IR) and European integration (EI) fail to conceptualise and to explain the phenomenon of European governance. The aim of this paper is to introduce policy networks as a better way of "exploring the nature of the beast". Coming from the field of comparative politics and public policy, policy networks have been largely ignored or strongly underestimated in international relations and European studies. This may be partly due to the many different, sometimes confusing ways the network concept is used in the literature. Therefore, this paper strives, in the first place, to review and to structure the existing literature on policy networks. It then explores the application of policy networks to the study of European governance. Finally, the strength and weakness of policy networks in studying European governance are discussed. The paper concludes that policy networks do not (yet) provide a new paradigm for European governance. However, they allow to grasp a unique feature of European governance conventional theories of IR and EI with their state-centred conception of governance cannot come to terms with.