Chlorination in various forms has been the predominant method of drinking water disinfection in the United States for more than 70 years. The seventh volume of the Drinking Water and Health series addresses current methods of drinking water disinfection and compares standard chlorination techniques with alternative methods. Currently used techniques are discussed in terms of their chemical activity, and their efficacy against waterborne pathogens, including bacteria, cysts, and viruses, is compared. Charts, tables, graphs, and case studies are used to analyze the effectiveness of chlorination, chloramination, and ozonation as disinfectant processes and to compare these methods for their production of toxic by-products. Epidemiological case studies on the toxicological effects of chemical by-products in drinking water are also presented.