This book is the first comprehensive study of the derecognition of states in world politics. It offers a global and comparative outlook of this under-explored diplomatic practice, guided by a new conceptual framework and informed by original empirical research. Although a great deal is known about the recognition of states, less is known about the practice of derecognition of states, namely why and how states withdraw the recognition of other contested and partially recognised states. The derecognition of states represents the withdrawal, revocation, or retraction of recognition of the international legal sovereignty of a state or government and in turn recognition or re-recognition of the sovereignty and authority of another state over the contested territory or derecognised state. The book looks at the process, justification, and effects of state derecognition, offering original insights from on four contested states which are currently experiencing withdrawal of recognition: Taiwan, Western Sahara, Abkhazia and South Ossetia, and Kosovo. The book argues that the derecognition of states plays a far greater role than we think in explaining the reversal politics and dynamics of secession and state creation, as well as understanding contemporary diplomatic battles that are shaping regional peace, increasing geopolitical rivalries, and endangering international order. This book fills a significant research gap in international relations, diplomatic studies, and international law.