Less than 100 million people live in the mountains and valleys of the Himalaya, but five times as many depend directly on water that flows down these steep slopes. Millions more can expect to benefit from prosperity in the Himalayan basin. This book brings out the role of the mighty mountains in regulating South Asia’s climate and the region’s water resource base. It underscores the promise and potential of Himalayan waters, and also introduced the complexities involved, both technical and political, in sharing the water in these rivers and solving the region’s water-related problems.