Fuzzy logic is a form of logic where truth values can be any real number between 0 and 1, unlike Boolean logic which only has the values of 0 and 1. It is used to model nonlinear systems more effectively than classical control methods. A fuzzy logic system has four main parts: fuzzification transforms crisp inputs into fuzzy sets, a knowledge base stores fuzzy IF-THEN rules, an inference engine simulates reasoning to make inferences on inputs and rules, and defuzzification transforms the fuzzy output into a crisp value. An example of fuzzy logic application is in anti-lock braking systems (ABS) for vehicles, which uses fuzzy rules to prevent wheels from locking during braking.