The Future Faces of Irregular Warfare: Great Power Competition in the 21st Century examines how modern conflict has shifted away from traditional battlefield wars and into a complex struggle for influence, legitimacy, and power. Produced by the Irregular Warfare Center, the book brings together leading military scholars and practitioners to explain how nations like China, Russia, and Iran compete below the threshold of open war using unconventional methods. Rather than tanks and troops, today’s conflicts rely on information warfare, economic coercion, cyber operations, proxy forces, legal manipulation, and narrative control. The contributors argue that irregular warfare is not new—but its scale, speed, and impact have dramatically increased in the digital age. Populations, not territory, have become the primary objective, and legitimacy is now the decisive center of gravity. The book explores real-world case studies, including Russia’s actions in Ukraine, China’s use of maritime militias, the weaponization of international law, climate-driven instability, and the rise of low-cost technologies like drones. A recurring theme is that the United States remains overly focused on conventional military solutions while adversaries exploit political, social, and informational vulnerabilities. Ultimately, the book calls for a whole-of-government and whole-of-society approach to security—one that integrates military power with diplomacy, economics, technology, and strategic communication. It serves as both a warning and a roadmap for policymakers and security professionals navigating great power competition in an era where wars are often fought without firing a single shot.