The development of Lasers has been a turning point in the history of science and engineering. It has produced a completely new type of systems with potentials for applications in a wide variety of fields. During sixties, lot of work had been carried out on the basic development of almost all the major lasers including high power gas dynamic and chemical lasers. Almost all the practical applications of these lasers in defense as well as in industry were also identified during this period. The motivation of using the high power lasers in strategic scenario was a great driving force for the rapid development of these high power lasers. In early seventies, megawatt class carbon dioxide gas dynamic laser was successfully developed and tested against typical military targets. The development of chemical lasers, free electron and X-ray lasers took slightly longer time because of involvement of multidisciplinary approach.