Although international relations is still a relatively young academic discipline in social sciences, the number of scientific works devoted to it, particularly those concerning foreign policy, is growing. However, the question of the definition of the object is still not clear-cut for this field of expertise with both explanatory and prescriptive, abstract and practical aims. Taken individually, the theoretical approaches to international relations seem to offer only partial portraits of the complexity that marks our era. This chapter highlights the value of combining different approaches if we are to have at our disposal powerful analytical tools to understand the dynamics of an increasingly interconnected and truly global world.