In the last thirty years optimization theory has been extensively applied to the optimal design of mechanical structures and, in general, to the solution of inverse problems in structural mechanics. In electromagnetism, however, the impact of optimization methods is much more recent. The present book is the first one on the subject of inverse problems and optimal design in electricity and magnetism. Filling this gap in the literature was the primary goal of the authors. The secondary one was to provide a comprehensive reference book offering a broad view of the subject ranging from theory to computer implementations. Having this in mind, the authors tried to write a book which might serve as a textbook for graduate students in electrical engineering as well as a reference for applied mathematicians and researchers. Possible applications pertain to a great many different areas: electrical machines, high voltage engineering, nuclear magnetic resonance spectrography, electron optics, plasma techniques, etc.