This chapter introduces the main approach developed in International Leviathans through (1) a sociological understanding of sovereignty and (2) the concept of international administration. First, the chapter presents a new take of the debate between Kelsen and Schmitt around sovereignty and presents the sociological understanding of sovereignty by unpacking sovereignty practices. It makes the case for analysing the socio-political or socio-legal struggles happening between competing claims of political authority and accountability. It then discusses and theorises the concept of ‘international administration’, pointing out the limitations of two strands of the literature: the functionalist approach, defining international administrations through the functions they ought to perform as underlined in their mandate, and the normative approach, focusing on self-proclaimed goals and objectives. I posit that sovereignty practices deployed by international officials are social practices which cannot be understood solely through mandates or stated goals – they need to be understood through the reality on the ground, created by claims of political authority deployed by actors and the concomitant claims of accountability these practices elicit.