At the outset, the subregions of East and North-East Asia are more dissimilar than similar, with different stages of development, economic structure and size, political systems and culture. Due to these differences and long standing historical and geopolitical tensions, institutionalized regionalization has not made much progress. Yet, there are increasing interactions, both officially and at the grassroots level, reflecting the growing importance and interdependence within this group of countries. From an economic standpoint, regional integration is more likely to be successful when countries have complementarities in factor endowments that can be shared to mutual benefit. This publication looks into how greater cooperation and integration could offer solutions to not only the old problems of poverty and political instability facing the subregion but also the new challenges posed by economic growth such as emerging income gaps, environmental degradation, urbanization and congestion and various social issues.