The word laser is an acronym for Light Amplification by Stimulated Emission of Radiation. Lasers are in fact generators of light. They are based on the amplification of light by means of stimulated - radiation of atoms or molecules. In 1917 Einstein predicted the possibility of such stimulated radiation. In 1952, Ch. Townes, J. Gorden, and H. Zeiger in USA and N. Basov and A. Prokhorov in USSR, independently suggested the principle of generating and amplifying microwave oscillations based on the concept of stimulated radiation. It led to the invention of MASER (Microwave Amplification by Stimulated Emission of Radiation) in 1954. In 1958 Townes, Basov, and Prokhorov received Noble Prizes for their work in this field. In 1960, Theodore Maiman of Hughes Research Laboratories produced the first laser using a ruby crystal as the amplifier and a flashlamp as the energy source. The first gas laser was developed in 1961 by A. Javan, W. Bennet, and H. Harriott of Bell Laboratories, using a mixture of helium and neon gases. Laser has become a valuable tool in a variety of fields starting with medicine to communications. Laser is a light source, but it is very much different from many traditional light sources. Laser is not used for illumination purposes as we use other light sources. Lasers produce a highly directional and high intensity beam with a narrow frequency range than that available from the common source types of light sources. They are more widely used as a light power electromagnetic beam rather than a light beam. Laser beans are used in the mechanical industry such as a special type of drill bit to drill in hard materials, and cutting materials like wood, glass, ceramics, etc. The laser is also used in the electronics industry such as scribing, soldering, trimming photolithography, etc. Application of lasers in the military involves mainly ranging, guiding weapons to the intended target and laser beam itself acting as a weapon, and so on. Thus, the laser is a high-technology device affecting our lives in many ways.