The book describes in detail the protection principles of each element of the power system network. The details of relay design and relay setting have also been covered. Further, the book contains a wide coverage of digital/numerical relaying scheme. Besides the relays, the book covers detailed theories of circuit breaking phenomenon and the construction and working of switchgears. The book is pedagogically rich with detailed relay and circuit diagrams, numerous solved examples, review questions, multiple-choice questions, and numerical exercises in each chapter. At the end of the book, an additional chapter on recent developments in protective relays covers the application of AI techniques in protective relays and discusses the concept of synchronized phasor measurements, wide area protection, along with other important topics.