Fuzzy logic is a simple phrase that actually refers to a large subject dealing with a set of methods to characterize and quantify uncertainty in engineering systems that arise from ambiguity, imprecision, fuzziness, and lack of knowledge. This 15-chapter textbook remains the only major text that can be used for both undergrduated and graduate classroom instructionin this technology field. The first eight chapters of the text cover fundamental materials useful in characterizing various forms of uncertainty and in developing the methods to quantify these uncertainties. Four chapters present specific case studies in decision making, classification and pattern recognition, control, simulation, and fuzzy arithmetic. there is one chapter on miscellaneous applications of fuzzy logic, one chapter on new rule-reduction techniques, and the final chapter presents material on other uncertainty theories with examples using evidence theory, possibility theory, and probability theory.