This book is primarily designed for courses in Microwave Engineering for undergraduate students of Electronics and Communication Engineering. Besides, it would be a useful text for students pursuing AMIE courses and M.Sc. students pursuing courses in physics and electronic sciences. The book explains the basic principles with a view to providing the students with a thorough understanding of microwave devices and circuits. It explains the analysis and design techniques used in microwave engineering. It provides a unified presentation of solid-state devices, microwave tubes (TWTs), klystrons, magnetrons and microwave circuits. Concentrating on clarity of explanation, the text provides a comprehensive presentation of the relevant theoretical aspects to allow students to easily assimilate this highly mathematical subject.