This module provides students with a comprehensive introduction to the study of international relations (IR). We begin by outlining the main theoretical approaches which aim to explain the behaviour of state and non-state actors in the international system – Realism and Liberalism - as Post-positivist theoretical perspectives such as Constructivism. The questions and issues to be examined in the course are introduced; emphasizing the scientific or theoretical study of international relations. In this section, we then examine the theoretical approaches to IR in depth, providing the student with alternative sets of theoretical lenses through which the world can be viewed. Here we highlight in detail some of the key disputes and differing concerns which separate the competing schools of thought. Furthermore, we study in detail an application for each school, highlighting an important contribution of that particular school to the study of IR.