The subject of the book could be described as fuzzy discrete structures. The book deals with fuzzy logic, fuzzy switching functions, fuzzy decision trees, fuzzy networks, fuzzy petri nets, fuzzy path problems, fuzzy automata, and fuzzy languages. The notion of a fuzzy decision tree and a branch-bound-backtrack algorithm is presented. In the appendix, this algorithm is described in C++. Network flow problems with various capacities are examined. Fuzzy shortest path techniques are presented whereby there is an actual path which corresponds to the fuzzy shortest path. Recent results on fuzzy automata and fuzzy languages are also presented.