In this chapter we set out to draw a diagram of religion and culture in world affairs. The aim was to show that religious and cultural factors matter if we want to deepen our understanding of international relations. The method has been to define elements of each concept and consider the impact of these elements on aspects of our individual, national and international experience. Hopefully, you are convinced that understanding religious and cultural issues is necessary if you want to join some of the most important discussions about world politics today. There is little that concerns IR today that does not involve elements of religion or culture, or both. Equally, it is important to recognise as a final thought that we have only just begun to explore these issues and we need to go deeper in our consideration of the importance of religious and cultural actors and interests. Understanding them will help us better understand an ever more complex and divided world.