Einstein''s Special Theory of Relativity describes the motion of particles moving at close to the speed of light. Einstein''s theory is now very well established as the correct description of motion of relativistic objects, that is, those traveling at a significant fraction of the speed of light. Einstein replaced the laws of Newton and Galileo with his theory of special relativity which showed how space and time are really related. In this book, we have extensively studied some relativistic transformations based on force and discussed the invariance properties in the light of space and time. We have also investigated that the relativity principle and the Lorentz force law enables us to cancel the Lorentz transformation and its time dilation from the main body of special relativity theory. The applicability of the special theory of relativity for inertial reference systems based on the symmetry of space and time that Lorentz transformation of the special theory of relativity is the only possible relationship between the coordinates and time in inertial reference systems, as well as its findings are requirements imposed by the conditions of the symmetry of space and time.