Surface Water-Quality Modeling by Steven C. Chapra is a comprehensive guide on using mathematical models to understand and solve water quality problems in rivers, lakes, and estuaries. The book covers foundational concepts like mass balance and reaction kinetics, as well as advanced topics like toxic substance modeling and simulations in flowing waters. Its main contribution is providing a practical approach that connects scientific theory with engineering tools, helping professionals and students predict pollutant impacts and make effective decisions to protect surface water resources.