Motion and Relativity focuses on the methodologies, solutions, and approaches involved in the study of motion and relativity, including the general relativity theory, gravitation, and approximation. The publication first offers information on notation and gravitational interaction and the general theory of motion. Discussions focus on the notation of the general relativity theory, field values on the world-lines, general statement of the physical problem, Newton's theory of gravitation, and forms for the equation of motion of the second kind. The text then takes a look at the approximation method and the equations of motion and motion and the Newtonian and post-Newtonian approximation. Topics include general remarks on the approximation method, two forms of the equations of motion and integrability conditions, approximation method and coordinate system, and development of the metric field. The manuscript examines the variational principle and the equations of motion of the third kind and the one and two particle problems. The formulation of the problem, Lagrangian up the sixth order, motion of a test particle in the field of a heavy particle, two-body problem, and motion of rotating bodies are discussed. The text is a dependable reference for readers interested in the methodologies, solutions, and approaches involved in the study of motion and relativity.