The idea that war is sometimes justified is deeply embedded in public consciousness. But it is only credible so long as we believe that the ethical standards of just war are in fact realizable in practice. In this engaging book, Christopher Finlay elucidates the assumptions underlying just war theory and defends them from a range of objections, arguing that it is a regrettable but necessary reflection of the moral realities of international politics. Using a range of historical and contemporary examples, he demonstrates the necessity of employing the theory on the basis of careful moral appraisal of real-life political landscapes and striking a balance between theoretical ideals and the practical realities of conflict. This book will be a crucial guide to the complexities of just war theory for all students and scholars of the ethics and political theory of war.