Effectively managing increasingly scarce transboundary water resources in many parts of the world may become one of the most critical challenges facing the international community in the 21st century. Forty per cent of the world's population depends on transboundary water resources, a situation that raises serious concerns at the international level. Unresolved issues of water resource use and allocation may create the potential for serious interstate conflicts and undermine regional stability. It is imperative that existing and potential disputes over access to shared water resources are resolved through peaceful means within the framework of legal principles and norms provided by international law. This book contains the complete collection of the ILA rules on international water resources, together with comments, explanatory notes and other supporting materials.