There was a time when the academics in dentistry spurned a new tachnology that had been advancing for more than a decade. This technology gave a new boom to dentistry. It overcomes all the technical difficulties faced in conventional dentistry. Due to this there is urgent need of popularising laser in dentistry. Dental practitioners always had query regarding lasers. The few basic questions which always kept coming regarding laser like; What is Laser?, How its work?, What is the principle of laser? and so on.. will be solved here. This monogram consists the answers of all the queries regarding laser.