At a time when international relations theory is being criticized for its lack of relevance, this book seeks to uncover theoretical and empirical knowledge about international conflict, crisis and war by exploring and testing new avenues of research. With chapters on enduring rivalries, crisis bargaining, world wars, strategic surprise, defence allocations, war termination and conflict resolution, the contributors collectively develop a stronger foundation for answering pressing questions about the onset, escalation and de-escalation of different forms of international violence from nineteenth century conflict to nuclear crises.