The book is devoted to the development of Einstein's theory of gravitation, based on the relativity of space-time and projectively invariant equations of gravitation. It eliminates contradiction of the theory with the modern field theory, because both descriptions of gravity - as a curvature of the Riemannian space-time and as a field in the Minkowski space - are not mutually exclusive. On this basis, some of the fundamental problems of the theory and relativistic astrophysics are revised. It is shown, in particular, that the spherically symmetric field does not have a singularity, the energy of the gravitational field of a point mass is finite, and the accelerated expansion of the Universe is a consequence of gravity properties. The book is intended for physicists and astrophysicists. However, it is also apprehensible for senior students.