This book explains the law relating to the conduct of hostilities and provides guidance on difficult or controversial aspects of the law. It covers who or what may legitimately be attacked and what precautions must be taken to protect civilians, cultural property, or the natural environment. It deals with the responsibility of commanders and how the law is enforced. There are also chapters on internal armed conflicts and the security aspects of belligerent occupation. This third edition has been brought up to date in the light of recent conflicts, especially the occupation Iraq by allied forces in the period 2003-04. Also included are the more recent judgments and opinions of the International Criminal Tribunal for the former Yugoslavia, the International Court of Justice and the European Court of Human RIghts, the comprehensive work of the ICRC with regard to customary international humanitarian law and the meaning of "direct participation in hostilities", the Harvard University air and missile warfare project, the San Remo Manual on non-international armed conflicts, the UK Law of Armed Conflict Manual of 2004 and several excellent monographs.