to Fuzzy Sets.- to Fuzzy Sets.- Fuzzy Mathematics.- Fuzzy Sets¿Basic Definitions.- Extensions.- Fuzzy Measures and Measures of Fuzziness.- The Extension Principle and Applications.- Fuzzy Relations and Fuzzy Graphs.- Fuzzy Analysis.- Possibility Theory vs. Probability Theory.- Applications of Fuzzy Set Theory.- Fuzzy Logic and Approximate Reasoning.- Expert Systems and Fuzzy Control.- Pattern Recognition.- Decision Making in Fuzzy Environment.- Fuzzy Set Models in Operations Research.- Empirical Research in Fuzzy Set Theory.- Future Perspectives.