This book reports about new advances and different approaches in dealing with impedance spectroscopy including theory, methods and applications. Impedance spectroscopy is a widely used and interesting measurement method applied in many fields of science and technology such as electro chemistry, material science, biology and medicine. In spite of the apparently different scientific and application background in these fields, they share the same measurement method in a system identification approach and profit from the possibility to use complex impedance over a wide frequency range and giving interesting opportunities for separating effects, for accurate measurements and for simultaneous measurements of different and even non-accessible quantities. For Electrochemical Impedance Spectroscopy (EIS) competency from several fields of science and technology is indispensable. Understanding electro chemical and physical phenomena is necessary for developing suitable models. Suitable measurement procedures should be developed taking specific requirements of the considered application into account. Signal processing methods are very important for extracting target information by suitable mathematical methods and algorithms. New trends are emerging rapidly involving special techniques for realizing fully automatic embedded solutions at low costs and requiring a deep overview of modern information technology.