This book provides a foundation for understanding water resources management in the Western states. The book threads together three important subject areas into a single, concise narrative, providing the reader with an understanding of the fundamentals behind water management policies and practices. The book is organized into three parts, each addressing an important aspect of the subject: Part 1 provides information on natural systems and the basics of hydrology, Part 2 provides an overview of water rights, and the legal concepts that have been adopted to allocate water resources to various uses, and Part 3 provides context for future allocations of water resources by describing influential factors and recent data trends. It is a timely piece of work as we educate the next generation on long-standing water issues and emerging concerns about water resource management in the Western states.