The beginning of the laser is attributed to the famous scientist Albert Einstein, who published the paper "On the Quantum Theory of Radiation" in 1917 and suggested the idea of the stimulated emission of radiation and established the theoretic foundations for the laser. Numerous researchers have worked on his ideas and developed them since then, and laser research has produced a variety of improved and specialized laser types and extended the range of its uses to various fields including physics, chemistry, biology and medicine. The following is an attempt to list (some of) the most important discoveries and achievements that have contributed to the significant development in laser research.