This volume of theYearbook of International Humanitarian Lawtakes a close look at the role of so-called “expert manuals” in the interpretation and development of the international law of armed conflict and connected branches of international law relating to military operations. While these manuals can and do play an undoubtedly useful role, their proliferation raises a number of questions. What degree of authority do they have and how much weight should be given to the views expressed in them? What is the methodology they employ and how effective is it in ensuring an as objective and...