Just and Unjust Wars: A Moral Argument With Historical Illustrations by Michael Walzer (1977) is a foundational text in modern ethics that analyzes the morality of warfare through historical examples ranging from antiquity to the Vietnam War. It argues that war is not exempt from moral judgment, defining the ethical limitations for initiating (jus ad bellum) and conducting (jus in bello) conflict. The work serves as a guide for when fighting is allowed and how it should be conducted, challenging the idea that all's fair in love and war.