The book is one of the fundamental works in theoretical physics. It contains the foundations of the special theory of relativity and all sections of classical physics within the framework of relativistic theory: mechanics of point and media, electrodynamics, wave field theory and thermodynamics. The second part of the book, devoted to the general theory of relativity, outlines the foundations of Riemannian geometry and Einstein's theory of gravity. Lagrangian formalism, conservation laws, cosmological and astrophysical problems, experimental justifications of the general theory of relativity are considered. The book was written with great pedagogical skill. It will undoubtedly become a reference book for the widest range of readers.