This book is the first comprehensive manual on the law of armed conflict, prepared by a team of expert scholars and practitioners working for and with the UK Ministry of Defence. It covers all aspects of the law of armed conflict as applied today, including means and methods of warfare, the treatment of civilians, and other non-combatants - including prisoners of war - and the conduct of operations in all three environments: land, sea, and air. It also includes discussion of some of the key elements of relevance in the modern strategic environment, not least, the legal aspects of internal armed conflict and the application of the law during peace support operations. This is a significant publication providing sound evidence of the legal views of one of the five Permanent Members of the UN Security Council. As such, it will become an essential reference and source for legal scholars working in this field, for officials working in foreign and defence ministries around the globe, and for military officers and lawyers requiring a sound grasp of the legal framework of military operations.