National and international interest in finding rational and economical approaches to water-quality management is at an all-time high. Insightful application of mathematical models, attention to their underlying assumptions, and practical sampling and statistical tools are essential to maximize a successful approach to water-quality modeling. Chapra has organized this user-friendly text in a lecture format to engage students who want to assimilate information in manageable units. Comical examples and literary quotes interspersed throughout the text motivate readers to view the material in the proper context. Coverage includes the necessary issues of surface water modeling, such as reaction kinetics, mixed versus nonmixed systems, and a variety of possible contaminants and indicators; environments commonly encountered in water-quality modeling; model calibration, verification, and sensitivity analysis; and major water-quality-modeling problems. Most formulations and techniques are accompanied by an explanation of their origin and/or theoretical basis. Although the book points toward numerical, computer-oriented applications, strong use is made of analytical solutions. In addition, the text includes extensive worked examples that relate theory to applications and illustrate the mechanics and subtleties of the computations.