  The interpretations of solutions of Einstein field's equations led to the
prediction and the observation of physical phenomena which confirm the
important role of general relativity, as well as other relativistic theories in
physics. In this connection, the following questions are of interest and
importance: whether it is possible to solve the gauge problem and of its
physical significance, which one of the solutions gives the right description
of the observed values, how to clarify the physical meaning of the coordinates
which is unknown a priori, and why applying the same physical requirements in
different gauge fixing, we obtain different linear approximations. We discuss
some of the problems involved and point out several open problems. The paper is
written mainly for pedagogical purposes.
