The material in thiook is presented in a logical sequence rather than a historical sequence. Thus, we feel obligated to sketch briefly the history of the special theory of relativity. The brilliant experiments of Michelson and Morley in 1887 demonstrated the astonishing fact that the speed of light is independent of the state of relative linear motion of the source of light and the observer of the light. This fact necessitates the modification of the usual Galilean transformation (between two relatively moving observers), which tacitly assumes that time and space are absolute.