This article reveals the essence of the special theory of relativity. There are no scientific arguments against the evidence presented in this article while it was uploaded for discussion as a preprint on the website of ResearchGate (the social networking site for scientists and researchers). The article starts with a general introduction to the problem in modern physics about the constancy of the speed of light for all frames of reference. In the “General Introduction” is presented the fundament of a real solution about all “unexpected” and “inexplicable” results of the experiments related to the measurement of the velocity of light in the time-spatial region “on the Earth surface”. The presented analysis of the article “On the Electrodynamics of Moving Bodies”, where Einstein presents the special theory of relativity, is based on the classical mechanics and Galilean relativity which are indisputably valid and lawful in our local time-spatial domain “near the Earth's surface”. Before the analysis, the foundations of our perception of the absoluteness of space and time are shown. The presented analysis of the article “On the Electrodynamics of Moving Bodies” shows exactly where and how the erroneous claim that “the speed of light is the same in all inertial reference frames” is applied. Einstein’s conclusion that “We cannot give any absolute meaning to the concept of simultaneous” was revealed to be based solely on this erroneous claim. This claim, however, has been experimentally proven to be false. Only the experiments, that use Michelson’s idea of two-way interferometers cannot fix the difference in the measured speed of light in different directions, because the difference in the speed of the two light beams in the direct and opposite directions is completely and exactly compensated”. The undoubted conclusion is that the special theory of relativity is the biggest delusion in physics of the 20th century. KEY WORDS: special theory of relativity; speed of light postulate; Michelson-Morley experiment; æther; speed of light invariance, On the Electrodynamics of Moving Bodies.