This new fifth edition of Laser Principles includes corrections to the previous edition. The text's primary task remains the same: to provide a broad but standardized description of laser behavior, physics, technology, and current applications. Dr. Svelto emphasizes the physical rather than the mathematical aspects of lasers, and introduces the topic in the simplest terms consistent with a correct physical understanding. Praise for previous versions: "Professor Svelto is himself a long-time laser pioneer and his text shows his extensive knowledge of all aspects of the field... Whoever masters the contents of this book will be well prepared to understand advanced theses and research papers in laser science and technology." (Arthur Schawlow, 1981 Nobel Prize Winner in Physics) "Professor Svilto's book, in this clear translation of David Hanna, can be highly recommended for self-study or teaching in the final year of university or first year of university." (Physics Bulletin) "A comprehensive understanding of this book in conjunction with one of the existing volumes on laser safety will go a long way in providing a health physicist with the understanding he needs... (Health Physics) “It offers laser science and technology with appropriate accessibility for non-specialists and the enthusiasm of pioneers.