A network may refer to “a group of interdependent actors and the relationships among them,” or to a set of nodes linked by a web of interdependencies. The concept of networks has its origins in earlier philosophical and sociological ideas such as Jean-Jacques Rousseau’s “general will” and Émile Durkheim’s “social facts”, which adressed social and political communities and how decisions are mediated and ideas are structured within them. Networks encompass a wide range of theoretical interpretations and critical applications across different disciplines, including governance networks, policy networks, public administration networks, social movement networks, intergovernmental networks, social networks, trade networks, computer networks, information networks, and neural networks. Governance networks have been proposed as alternative pluricentric governance models representing a new form of negotiated governance based on interdependence, negotiation and trust. Such networks differ from the competitive market regulation and state hierarchical control in three aspects: the relationship between the actors, decision-making processes, and compliance. The decision-making processes within governance networks are founded on a reflexive rationality rather than the “procedural rationality” which characterizes the competitive market regulation and the “substantial rationality” which underpins authoritative state regulation. Network theory has proved especially useful for scholars in positing the existence of loosely defined and informal webs of experts or advocates that can have a real and substantial influence on international relations discourse and policy. Two examples of the use of network theory in action are transnational advocacy networks and epistemic communities.