Leading political theologian Oliver O'Donovan here takes a fresh look at some traditional moral arguments about war. Modern Christians differ widely on this issue. A few hold that absolute pacifism is the only viable Christian position, others subscribe in various ways to concepts of 'just war' developed out of a Western tradition that arose from the legacies of Augustine and Aquinas, while others still adopt more pragmatically realist postures. Professor O'Donovan re-examines questions of contemporary urgency including the use of biological and nuclear weapons, military intervention, economic sanctions, war crimes trials and the roles of the Geneva Convention, international conventions and the UN. His enquiry opens with a challenging dedication to the new Archbishop of Canterbury and proceeds to shed new light on vital topics with which the Archbishop and others will be very directly engaged. It should be read by anyone concerned with the ethics of warfare.