Water, water resources and water resource management have become one of the most challenging non-traditional cross-border security problems for humankind today. In this anthology, based on first-hand documents, experts try to provide an insightful understanding of why the Greater Mekong Subregion is important from a geo-strategic perspective, what historical and current challenges the region faces, how great powers, including China, India, Japan and the US, are involved in the Greater Mekong Subregion, and what that region can learn from other regions with regard to water resource management.