'As the world confronts fresh threats, ranging from new great powers determined to challenge the existing international order to apocalyptic non-state armed groups determined to destroy that order entirely, there is renewed urgency to consider questions about the justice of war. Thankfully, in this important new book, Paul D. Miller, shows how we can do that. It combines a rare blend of sophisticated and careful historical analysis that yields not one but three just war traditions with the sort of insight into the critical dilemmas of today that can only stem from practical experience on the front line. Doing so, it both expertly illuminates the past in a fresh way and provides a compelling moral framework for thinking about, and debating, the challenges we face today, and will come to face tomorrow.' Alex J. Bellamy, Professor of Peace and Conflict Studies, The University of Queensland, Australia