1. Notes on contributors; 2. Introduction David Armstrong and Theo Farrell; 3. Legitimacy and the use of force: can the circle be squared? Andrew Hurrell; 4. Legality and legitimacy: the quest for principled felxibility and restraint Richard Falk; 5. Not yet havoc: geopolitical change and the international rules on military force Michael Byers; 6. Liberal hierarchy and the license to use force Christian Reus-Smit; 7. The age of liberal wars Lawrence Freedman; 8. Force, legitimacy, success and Iraq David Campbell; 9. War and international relations: a military historical perspective on force and legitimacy Jeremy Black; 10. The judgement of war: on the idea of legitimate force in world politics Nicholas Rengger; 11. Discourses of difference: civilians, combatants and compliance with the laws of wars Helen M. Kinsella; 12. Fights about rules: the role efficiacy and power in changing multilateralism Martha Finnemore; 13. Peacekeeping and enforcement action in Africa: the role of Europe and the obligations of multilateralism Christine Gray; 14. Dead or alive: American vengeance goes global Michael Sherry.