The design and development of electrical devices involves choosing from many possible variants that which is the best or optimum according to one or several criteria. These optimization criteria are usually already clear to the designer at the statement of the design problem. The methods of optimization considered in this book, allow us to sort out variants of the realization of a design on the basis of these criteria and to create the best device in the sense of the set criteria. Optimization of devices is one of the major problems in electrical engi neering that is related to an extensive class of inverse problems including synthesis, diagnostics, fault detection, identification, and some others with common mathematical properties. When designing a device, the engineer ac tually solves inverse problems by defining the device structure and its pa rameters, and then proceeds to deal with the technical specifications followed by the incorporation of his own notions of the best device. Frequently the so lutions obtained are based on intuition and previous experience. New meth ods and approaches discussed in this book will add mathematical rigor to these intuitive notions. By virtue of their urgency inverse problems have been investigated for more than a century. However, general methods for their solution have been developed only recently. An analysis of the scientific literature indicates a steadily growing interest among scientists and engineers in these problems.