Introduction

This chapter seeks to introduce the reader to the most prominent International-Relations (IR) theories which have shaped the discipline as it approaches its centenary. It begins with a discussion of Realism, before turning to Liberalism, Marxism, Constructivism and Critical Theories. It is important to remember that the role of IR theory is to help to identify patterns and to generalise at an international level, not to understand the factors which affect decision-making processes. Theories help us to do this, but they are not normally theories that diplomats and state officials seek to act out on the international stage. A foreign policy can be understood through the lens of Constructivism; but that would not make it a Constructivist foreign policy, in the sense of a policy maker setting out to enact what she or he may imagine a Constructivist foreign policy to look like.