The term "middle power" is conceptually fragile. Some scholars have even argued for abandoning it. This book argues that the concept needs to be analysed more profoundly and that new analytical tools need to be developed to better understand the phenomenon. The traditional approach, based on Western states, is insufficient and has become increasingly irrelevant in a transformed global environment. Instead of drawing from a single theory of international relations, the contributors have chosen to build upon a wide range of theories in a deliberate demonstration of analytic eclecticism. A pluralistic approach provides stronger explanations while remaining analytically and intellectually rigorous. Many of the theory contributions are reconsidering how the largely "Western" bases of such theorising need revising in light of the "emerging middle powers", many of which are in Asia. Presenting a strong argument for studying middle powers, this book explores both the theory and empirical applications of the concept by rethinking the definition and characteristics of middle powers using a range of case studies. It examines changes in the study of middle powers over the last decade, proposing to look at the concept of middle powers in a coherent and inclusive manner. Finally, it aims to further the discussion on the evolution of the international system and provides sound conclusions about the theoretical usefulness and empirical evolution of middle powers today.