Quantum Electronics, Volume 1: Basic Theory is a condensed and generalized description of the many research and rapid progress done on the subject. It is translated from the Russian language. The volume describes the basic theory of quantum electronics, and shows how the concepts and equations followed in quantum electronics arise from the basic principles of theoretical physics. The book then briefly discusses the interaction of an electromagnetic field with matter. The text also covers the quantum theory of relaxation process when a quantum system approaches an equilibrium state, and explains the role of the relaxation process in quantum electronics. The book then presents the possible quantum effects in ordinary electronics at very high frequencies and low temperature conditions. The behavior of quantum systems interacting in weak and strong fields and the equations of motion for two- and three-level systems are analyzed. The text also explains the theory of spontaneous and stimulated emission and this theory''s association with classical theory. The book then takes up the development of lasers. The text explains that the laser''s capability to generate concentrated electromagnetic fields with a very small spectral width can be used with the linear electro-optical effect, the Kerr effect, and the Faraday effect for better research. Readers with some knowledge in theoretical physics, particularly on quantum mechanics, will find this book valuable.