This research monograph presents the fundamentals of fuzzy control theory and recent results in extending fuzzy control theory for multivariable and large-scale systems. Among the topics presented are: the problem of dimensional reduction of fuzzy relations; the possibilities for decomposing multivariable systems for the purpose of distributed fuzzy control; a method of two-level hierarchical fuzzy control, based on local and global control components; methods of decentralized fuzzy control by different types of spatial decomposition of the original system into subsystems, and, analogously, methods of multilayer fuzzy control on the basis of several types of temporal decomposition of the original system into layers. The theoretical results are illustrated by numerical examples and two case studies. It is shown that the number of fuzzy relations, respectively on-line computations, can be significantly reduced and in this way real-time control implementation can be facilitated. The book is written using a structured method-algorithm-example format, and offers solutions to existing problems, as well as pointing a way to further investigations.