This book covers the use of fuzzy techniques in the operation and planning optimization of electric distribution systems, described in a tutorial way. The book also focuses on the use of clustering techniques for a better modeling and controlling of the process by means of the Fuzzy Techniques.Most of the algorithms described in the book are explained in a detailed manner, allowing straightforward implementation. This level of detail is intended to familiarize the reader with some of the crucial questions regarding the numerical application of Fuzzy Techniques: how algorithms operate, why they converge, difficulties that may be encountered and their possible remedies.