This book elaborates on Wavelet Theory and its applications in various fields. The application of wavelet transformation to examine the behavior of complex systems from several fields has begun to be widely identified and applied successfully during the past few decades. The book deals with three major aspects of Wavelet Transformation i.e. Electrical Systems, Fault Diagnosis and Monitoring, and Signal Processing. One of the important characteristics of this book is that the wavelet concepts that are applied in engineering, physics and technology have been discussed from a point of view that is recognizable to researchers from different branches of science and engineering. The text of the book is worth utility to a large number of readers.