In recent years, the world has witnessed a reassertion of informal clubs of powerful states in various areas of global governance. Scholarly views on the implications of this trend are highly diverse. While some observers a priori reject this kind of cooperation for being illegitimate, others believe that such smaller negotiating venues may promote better cooperation among the most pivotal countries and can even provide international leadership. This book has attempted to conduct an objective assessment of the performance of the G8 and G8-related concerts of major powers in governing global energy challenges. The concert-method was evaluated along two dimensions. First, we examined whether leadership had been provided. Second, we evaluated whether sustainable energy choices had been made. The benchmark for the leadership criterion was the theoretical framework developed in Chapter 5 and the touchstone for the sustainability criterion was put forward in Chapter 2. Here, we present a round-up of the results of this assessment before addressing the question of how concert-like forums could be rendered more efficient and legitimate. Finally, we explore some ideas that are currently circulating to reinforce the collective management of global energy issues.