This book uses the Russian invasion of Ukraine as a compelling and dramatic case study to engage with ten key concepts of International Relations (IR).By focusing on enduring concepts, rather than fleeting events, it provides students and experts alike with a lasting framework for understanding 21st-century international conflicts. Each chapter is written by a leading scholar, providing innovative, critical thinking that sheds light on a specific aspect of the Russo- Ukrainian War. Rigorous analysis, expert insight, discussion of relevant debates, recent literature, and reference works provide readers with an in-depth exploration of key concepts through the lens of interstate war. The book offers readers a comprehensive approach that includes a mastery of the most important concepts in IR; an exploration of the main debates surrounding each of these concepts; and an empirical analysis of the war.Its accessible style and conceptual, pedagogical, and empirical contributions will make it a valuable resource for students, scholars, and practitioners seeking to deepen their understanding of 21st-century international politics, security studies, foreign policy analysis, and strategic studies.