If moral clarity about decisions to wage war ever existed, it is certainly missing today. As the wars of conquest and territorial defense that marked earlier eras have given way to “wars of choice,” limited military actions, and humanitarian interventions, the moral principles that leaders might wish to invoke when contemplating the use of military force have become increasingly murky. In this thoughtful treatise, a former British defense official provides a welcome restatement of the “just war” tradition in the context of current security challenges. In part, the book is a survey of religious and secular thinking about morality and war. But Fisher’s main interest is in identifying the changing moral choices and circumstances that confront contemporary would-be war-makers. Preemptive war, humanitarian intervention, strategic bombing, torture -- Fisher probes these and other controversial areas of modern-day warfare, arguing for the relevance of just war principles. The book eloquently makes clear that no one, from the soldier in the trenches to the commander in chief, can escape moral choice. The only question is whether one’s choices are worthy and well reasoned.