The objective of writing this book to be to provide the reader with a text that presents a lucid and comprehensive treatment of transformers and more common types of rotating electrical machines. The philosophy of the book is to emphasize the physical understanding of the basic principles underlying the operation of electrical machines. In order to achieve this goal, the theory is developed from elementary ideas in such a style that their physical concepts are highlighted. The magnetic flux view point has been employed throughout this book, as this approach is easily understood and appreciated by the students. In addition, this approach provides a deep insight into the internal behaviour of electrical machines, so important that these concepts only show the way to creative engineering and become the most valueable asset of student’s education. Each chapter takes off from the first fundamentals and is so developed progressively that an average student can group it easily. Clarity of presentation is further augmented by an appropriate use of illustrative figures and a wide variety of worked examples. Each chapter concludes with numerous unsolved problems with answer, conceptual questions and hints to the relatively difficult ones.