This work explores humankind’s need for ownership, wealth and dominance which can lead to war, and a nationalistic approach with national identity based on the corporate memory and the clash of morality and ethical systems. It explores pacifism and political reality and outlines the modern era of war. The book explores how war starts and whether it can be justified, examines conduct in war, and how such conflict can be resolved in the postwar period. It portrays the arguments by referring to many historical incidents. The book concludes with the legal and moral arguments relating to war, and an examination of contemporary tensions in North Korea and Taiwan, and the war in the Ukraine. The book aims to be a concise and clear study of war, of interest to students and researchers in moral philosophy, as well as conflict studies and peace studies.