<div>The main theme of this volume of the <i>Yearbook of International Humanitarian Law</i></div><div>is the development and interpretation of international humanitarian law (IHL). It is</div><div>elaborated upon in several chapters that examine the role of non-state armed groups</div><div>in the development and interpretation of IHL, the impact of international criminal law</div><div>on the development of IHL, the notion of external non-international armed conflicts,</div>and the regulation of prolonged occupation under international law. <div><br></div><div>The second theme of this volume is dedicated to targeting in armed conflicts. Specific</div><div>topics include precautions in attack in urban and siege warfare, the targeting of the</div><div>Islamic State’s religious personnel in Iraq and Syria, and the targeting of illicit crops</div><div>through aerial spraying in Colombia. Besides the chapters that address both themes,</div><div>this volume also contains a <i>Year in Review</i> describing the most important events and</div><div>legal developments that took place in 2017. </div><div><br></div><div>The <i>Yearbook of International Humanitarian Law</i> is the world’s only annual publication</div><div>devoted to the study of the laws governing armed conflict. It provides a truly international</div><div>forum for high-quality, peer-reviewed academic articles focusing on this crucial</div><div>branch of international law. Distinguished by contemporary relevance, the <i>Yearbook</i></div><div><i>of International Humanitarian Law</i> bridges the gap between theory and practice and</div><div>serves as a useful reference tool for scholars, practitioners, military personnel, civil</div><div>servants, diplomats, human rights workers and students. </div>