Every form of social community involves friendship. When we look around, international politics presents us with numerous examples. We may cite the 'Franco-German friendship', the Anglo-American 'special relationship', and the former 'Sino-Soviet friendship'. The Treaty of Westphalia of 1648 proclaimed 'sincere Amity' among its signatories. Furthermore, the UN Charta is dedicated to promote 'friendly relations among nations'. While we find many instances of friendship discourse in international politics we know remarkably little about them. How can we conceptualize and study friendship in international relations? How is international friendship practiced and what empirical cases exist? This edited volume puts forward the argument that international friendship is a distinct type of interstate and international relationship, and that as such, it can contribute to capture aspects of international politics that have long remained unattended. To this end, Simon Koschut and Andrea Oelsner offer a framework for analyzing friendship in international politics by presenting a variety of conceptual approaches and empirical cases of international friendship.