The book "Principles of Lasers" by Orazio Svelto, translated and edited by David C. Hanna, is a comprehensive guide to the principles and applications of lasers. The third edition, published in 1989, has been revised to reflect significant developments in the laser field since the second edition in 1982. The book aims to provide a broad and unified description of laser behavior at a level that is accessible to students in electrical engineering, physics, and chemistry. Key additions in this edition include: 1. New sections on various laser types, such as x-ray lasers, solid-state lasers (including alexandrite devices), and an extended description of semiconductor lasers. 2. A more detailed treatment of laser mode-locking, including cavity dumping and pulse compression. 3. An extended and simplified explanation of the coherence and statistical properties of laser light compared to conventional light. 4. A more extensive discussion of the physics of gas discharges. The book covers introductory concepts, the interaction of radiation with matter, pumping processes, passive optical resonators, continuous wave and transient laser behavior, types of lasers, properties of laser beams, and laser beam transformation. It also includes appendices on semiclassical treatment of radiation-matter interaction, space-dependent rate equations, active mode locking theory, and physical constants. The book is designed for classroom teaching and self-study, providing a solid foundation in the principles of laser operation.The book "Principles of Lasers" by Orazio Svelto, translated and edited by David C. Hanna, is a comprehensive guide to the principles and applications of lasers. The third edition, published in 1989, has been revised to reflect significant developments in the laser field since the second edition in 1982. The book aims to provide a broad and unified description of laser behavior at a level that is accessible to students in electrical engineering, physics, and chemistry. Key additions in this edition include: 1. New sections on various laser types, such as x-ray lasers, solid-state lasers (including alexandrite devices), and an extended description of semiconductor lasers. 2. A more detailed treatment of laser mode-locking, including cavity dumping and pulse compression. 3. An extended and simplified explanation of the coherence and statistical properties of laser light compared to conventional light. 4. A more extensive discussion of the physics of gas discharges. The book covers introductory concepts, the interaction of radiation with matter, pumping processes, passive optical resonators, continuous wave and transient laser behavior, types of lasers, properties of laser beams, and laser beam transformation. It also includes appendices on semiclassical treatment of radiation-matter interaction, space-dependent rate equations, active mode locking theory, and physical constants. The book is designed for classroom teaching and self-study, providing a solid foundation in the principles of laser operation.