Powers and compensation in circuits with nonsinusoidal currents discusses one of the most controversial problems in electrical engineering; the definitions of electrical powers and compensation. Many approaches to explain the power properties of electrical circuits and their compensation has occurred over a vast number of publications and referred to as the “schools of power theory (PT)”. These debates have caused substantial confusion in the electrical engineering community. The development of the Current's Physical Components (CPC)-based power theory by the author of this book was a major contribution to the debate on powers and compensation. This book explains all the power-related physical phenomena in electrical circuits and creates fundamentals for compensation in circuits of any complexity with linear and nonlinear loads in single- and three-phase circuits using reactance, switching and hybrid compensators in terms of CPC-power based theory. It also discusses some common misinterpretations of power related phenomena. This book was written as a 'by-product' of more than 30 years of teaching at Louisiana State University of undergraduate and graduate courses on powers and compensation and supervising the development of graduate Msc. theses and Ph.D. dissertations. Therefore, this book can serve as a major reference for teaching power courses and for those involved in studies on powers and compensation in circuits with nonsinusoidal currents.