ABSTRACT
This chapter talks about theoretical reflection and analysis of North Atlantic Treaty Organization (NATO), Europe's most important security provider, and one of the central institutional pillars of the European security system. It then provides an overview of the richness and diversity of theoretical inquiry into NATO and transatlantic security cooperation, and indicates the potential for developing complex multi-causal analytical models. The chapter makes the case for theory as such, in general in the discipline of International Relations (IR) and in particular by reference to NATO. Within IR, there is a variety of different forms and types of theory. The most widespread and influential is 'explanatory theory', which seeks to explain events by identifying causal relationships. The need for theoretical pluralism, as well as a vibrant academic conversation on NATO, arises from the complex and multifaceted nature of the Alliance itself.
