The Koshi River basin resource book presents an analysis of the complexities inherent in effectively managing water resources. It collates current knowledge on the Koshi basin’s water resource system and related ecosystems, their uses and users, and integrated governance mechanisms. Building on these, it presents possible approaches for water management at different scales. The authors identify key knowledge gaps and provide specific recommendations that may be useful for policy makers, administrators, development workers, and researchers working on addressing water resource management issues in the basin.