The chapters in this book all examine and reflect on various aspects of the rules of war and the normative dilemmas that they throw up. In this context, naturally enough, there is little explicit discussion of the character of the moral world and how that shapes the possibility of our claims about the ‘rules of war’ and exceptions to them that are quite properly foregrounded in the individual chapters; torture and its (im)permissibility, for example, or such contemporary and topical notions like preventive war, the implications of nuclear technology and the notion and deployment of the idea of aggression.