Instrumental methods of chemical analysis have become the principal means of obtaining information in diverse areas of science and technology. The speed, high sensitivity, low limits of detection, simultaneous detection capabilities, and automated operation of modern instruments, when compared to classical methods of analysis, have created this predominance. Professionals in all sciences base important decisions, solve problems, and advance their fields using instrumental measurements. The book explains many details about one of the most important instrumental techniques used for different analytical applications. This technique is called Total Organic Carbon (TOC) Analyzer. This technique is used for water and wastewater examination using the standard analytical methods obtained from standard methods or united states- environmental protection agency (US-EPA). It is the most suitable technique used to explain theories and concepts of the instrumental analysis. It used in the central laboratories for analysis of drinking water and wastewater to show effect of the chlorination process in minimizing the organic pollutants.