A handbook on secession naturally covers the important legal and political issues that arise in the course of an entity’s transition to statehood. In this chapter, however, I consider what happens next. In other words, I will discuss the law of state succession. The chapter will proceed as follows. First, I provide a brief overview of the development and central tenets of the law of succession. Just like the creation of states, the law of state succession is a fundamental, foundational part of international law. When instances of state succession occur, in whatever form, the entire panoply of international legal rights and obligations applicable to the successor state (as well as any continuing state) potentially are affected.It is obviously not possible to consider all such rights and obligations here, so instead the chapter will focus on four main areas, state succession in relation to (a) treaties, (b) state property, archives and debts, (c) nationality, and (d) state responsibility. Finally, a more general critical evaluation of the current state of the law and how it may look in the future are considered. I argue that the law of state succession, if one accepts that the purpose of the law is to guide action, in its current form suffers from some serious defects and arguably does not fulfil this role. Rather, the transition to statehood is most often governed by ad hoc agreements between succeeding and continuing states. This suggests that the best way forward is to bolster a duty to negotiate such agreements in good faith, and to conclude pacta de contrahendo if agreement cannot be reached immediately, rather than persist with the development of general one-size-fits-all rules