Available open access digitally under CC-BY-NC-ND licence. The precarious status of contested states both reflects and begets conflict. From Taiwan to Western Sahara and from Nagorno-Karabakh to the Liberation Tigers of Tamil Eelam, contested states call into question the standard categories of international law that divide inside and outside, state and non-state, war and rebellion. They inevitably fall in-between them, while alternatively disputing and negotiating their applicability. Bringing together perspectives from a range of disciplines, the book focuses on some of the most entrenched conflicts around the world. It reveals how different actors, including de facto governments, parent and patron states, local populations, and international courts, navigate the grey zone as they redraw, or work around, the fault lines of war and law.