  Criteria for defining errors of a physical theory are formulated. It is shown
that the Special Theory of Relativity (STR) has a solid mathematical basis. An
enormous amount of experiments carried out in particle physics use beams of
particles having a very high energy. The data of these experiments are
consistent with STR and support our confidence that STR is an excellent theory.
Several specific cases of this issue are discussed explicitly. Contrary to a
common belief, it is proved that the contemporary mainstream of physicists
adhere to some theoretical ideas that violate STR.
