An eminent international line up of experts in law, political science, economics and history examine the dynamics of the European Union's (EU) development as a collective member of the G8 and G20. Each contribution provides a methodical and much needed insight into the external and internal factors influencing this evolvement process, the options for these institutions to reform and collaborate and the future role of the EU in this new system of institutions. Part One makes an introduction into the topic of the EU representation in the G8 and the main concepts explored in the book. Part Two presents an analytical framework for exploring the EU actorness in global governance institutions. Part Three examines the transformation of the G7/G8 system, the emergence of the G20 as a leader's forum and the EU role in the process. Part Four provides an in-depth analysis of the EU contribution to critical cases of global governance including issues of energy, finance, development, peace and security. Part Five analyses the main trends in leadership and models of engagement. Contributing to key contemporary debates, this book is a lucid replenishment to the existing literature on global governance and an excellent resource to studying the EU's role as a global actor.