There are four fundamentally important reasons why we should be interested in the theory and practice of regional leadership in East Asia. The first is that East Asia is now one of the most important regions in the global system, geopolitically and geoeconomically. What happens in East Asia has increasingly global impact, with China especially the focus of much attention in this respect. Second, East Asia is gradually becoming a more coherent regional entity through the interplay of various integrative economic, political and sociocultural processes. This will provide more scope for regional leadership to be exercised by relevant actors. Third, it may be viewed as an important litmus test for China’s approach to taking on international roles and responsibility, and exercising international leadership generally. Fourth, exercises of regional leadership in East Asia are likely to further strengthen the basis of a region-based multipolar world order, especially one where large developing nations are acting as ‘regional powers’, e.g. India in South Asia/Asia, Brazil in South America.