The discussions on East Asia, such as on the issues of East Asian regionalism, regional cooperation and community building, can be divided into five groups: the ``economic community discourse,`` ``political and security discourse,`` ``East Asian identity discourse,`` ``alternative social order discourse,`` and ``East Asian Community discourse.`` This study examines the differing arguments of ``East Asian Community discourse`` on the boundary and composition of East Asian community, on the objectives and principles in East Asian regionalism, and on the approaches and methods of East Asian community building. The recent changes in international situation including the political and economic rise of China, the US re-engagement in East Asia, and the financial crisis in Europe, have a profound impact on our discussion on East Asian regionalism. This study also examines the lessons that we learn from these changes and their implications in our efforts to promote East Asian regional cooperation and to build a viable regional community.