Economics brings powerful insights to water management, but most water professionals receive limited training in it. This text offers a comprehensive development of water resource economics that is accessible to engineers and natural scientists as well as economists. The goal is to build a practical platform for understanding and performing economic analysis using both theoretical and empirical tools. The mathematics needed to understand the subjects covered in this text include basic optimization methods and integral calculus. Familiarity with microeconomics or natural resource economics is helpful, but all the economics needed is presented and developed progressively in the text. Many water-based example calculations are included. Thus the book can be used for independent study as well as course work.The book focuses on the scarcity of water quantity (rather than water quality). The author presents the economic theory of resource allocation, recognizing the peculiarities imposed by water, and expands the theory to encompass time-defined matters such as ground water depletion. He then discusses such subjects as institutional economics, water law, how economics is used in policy and cost-benefit analysis, the roles of water marketing and water pricing, demand and supply estimation, privatization, and modeling with demand and supply functions. As an aid to readers with specific interests, references to recent literature are given for all of these topics. Each chapter ends with a summary and exercises. All graphic portrayals of economic theory and most calculations are performed using Mathematica software. These programs are downloadable, but their use is entirely optional.