This Encyclopedia provides a comprehensive account of the theoretical and practical development of international relations. Experts in the field examine the intellectual and political relevance of core concepts, from liberalism and constructivism to war and conspiracy. Each entry explores the meaning and historical role of a key concept within international relations, outlining the debates that shape the field. The Encyclopedia demonstrates the wide-ranging, diverse and interdisciplinary nature of international relations, highlighting both the foundations of the field and the cutting-edge ideas shaping it today. It serves as an excellent entry point for further research, with a mix of brief summative entries providing a concise introduction to the topic alongside longer entries covering the most complex concepts in the field. Key Features: * 179 accessible entries * Suggests further reading for each concept * Provides a carefully selected list of entries, reflecting the development