Is it legal to kill, or capture and confine, someone in war? Is this relevant or wise to ask in the reality of war? What does 'legal' actually mean in the labyrinth of overlapping international laws? This volume explores the meaning, relevance, and wisdom of questioning the 'legality' of the use of force against individuals in war by reconnecting legal thought with the social world. Weaving together law, social theories, and actual practices, the book presents an interdisciplinary study of the laws regulating warfare. The Use of Force against Individuals in War under International Law uncovers different conceptions of 'legality' that generate tensions among different international laws regulating warfare and highlights the limits of legal techniques in addressing these tensions. Accepting these tensions serves not to denigrate the law itself but to invite a deeper level of engagement with it - through the lens of social theories. Drawing on the insight that every social action results from an interaction between human agency and social structures, this publication argues that in regulating warfare, one distinct body of international law, the law of armed conflicts, accommodates the diminished agency of human beings operating in highly structured conditions while other bodies of international law harbour the potential to transform these very structured conditions. Thus, assimilating these laws, whether in court or real-world practices, fundamentally conflates their underlying social ontologies.