1. Introduction -- § 1. On the Beginning of Relativity -- § 2. The Space-Time Structure of Special Relativity and First Basic Consequences -- § 3. On the Operational Aspect of Physical Concepts -- § 4. New Ideas on Mass and Energy, in Contrast with Classical Physics, Accepted on the Basis of Special Relativity Kinematics -- § 5. On Forces, Cauchy Equations of Continuous Media, and the First Principle of Thermodynamics in Special Relativity -- § 6. On Electromagnetism, Heat Conduction, and Constitutive Equations in Special Relativity -- § 7. Gravitation and Relativity -- § 8. On the Local Equivalence Principle and the Basic Local Laws of the Electromagnetic Field and Continuous Media, Other than the Poisson Equation, in General Relativity. A Criterion Connecting those Laws with Their Analogues in Classical Physics or Special Relativity -- § 9. On the Invariance of Physical Equations and on the Possible Physical Equivalence of the Frames in which these Equations have the Same Form. On a Privileged Absolute Concept of Event Point -- § 10. On Harmonic Coordinates and the Existence of General Frames not Physically Equivalent in General Relativity -- § 11. Some Distinctive Properties of General Relativity. On the Equivalence of General Frames in General Relativity -- § 12. What We Mean by General Theory of Relativity -- § 13. On the Development of General Relativity. Inclusion of Elasticity, Electromagnitostriction, Couple Stresses, and Hereditary Phenomena -- § 14. Scope and Plan of the Present Tract -- Footnotes to Chapter 1 -- I. Basic Equations of Gravitation, Thermodynamics and Electromagnetism, and Constitutive Equations from the Eulerian Point of View -- 2. Space-Time Kinematics Including Masses -- 3. Gravitation and Conservation Equations. Fluids and Elastic Waves -- 4. Electromagnetism from the Eulerian Point of View. Polarizable Fluids -- 5. On Media Capable of Electromagnetic Phenomena from the Eulerian Point of View. Magneto-Elastic Waves in Ideal Conductors -- II. Materials from the Lagrangian Point of View -- 6. Kinematics and Stresses from the Lagrangian Point of View -- 7. Elasticity, Acceleration Waves, and Variational Principles for Simple Materials -- 8. Piezo-Elasticity and Magnetoelastic Waves from the Lagrangian Point of View -- 9. Materials with Memory and Axiomatic Foundations -- 10. Couple Stresses and More General Stresses -- Appendix A. Double Tensors -- §A1. Definition of Double Tensors Related to Two Topological Spaces -- §A2. Partial Covariant Derivative and Total Covariant Derivative Based on a Mapping -- §A3. On Differentiation of Double Tensors, Functions of Double Tensors -- Case of Arguments Fulfilling Typical Regular Conditions -- Appendix C. On the Divergence of Spatial Vectors in Space-Time -- References.