Principles of Quantum Electronics focuses on the concept of quantum electronics as the application of quantum theory to engineering problems. It examines the principles that govern specific quantum electronics devices and presents their theoretical applications to typical problems. Comprised of 10 chapters, this book starts with an overview of the Dirac formulation of quantum mechanics. This text then considers the derivation of the formalism of field quantization and discusses the properties of photons and phonons. Other chapters examine the interaction between the electromagnetic field and charged particles. This book discusses as well the interaction of radiation with free and bound electrons, with focus on the spontaneous and stimulated emission of radiation by bound electrons. The final chapter provides the investigation that Maxwell's theory can be regarded as the quantum theory of a single photon. This book is a valuable resource for graduate students, specialists, and engineers who are interested in the field of quantum electrodynamics.