This book is compiled in such a manner, that it will provide in-depth knowledge about the theory and practice of laser and laser technology. It will give deep insights about the applications of laser and its technology in fields like science, medical and engineering. Laser is an acronym for light amplification by stimulated emission of radiation. It is used in barcode scanners, optical disk layers, laser surgery, laser lightning displays, etc. This textbook presents the complex subject of lasers in the most comprehensible and easy to understand language. Most of the topics introduced in it cover new techniques and the applications of laser technology. Different approaches, evaluations and methodologies and advanced studies have been included in it. It will serve as a valuable source of reference for those interested in this subject.