Part I: The Special Theory of Relativity ......................................................................... 5
The System of Co-ordinates............................................................................................ 7
Space and Time in Classical Mechanics......................................................................... 9
The Galileian System of Co-ordinates.......................................................................... 10
The Principle of Relativity (in the restricted sense)...................................................... 11
The Theorem of the Addition of Velocities Employed in Classical Mechanics........... 13
The Apparent Incompatibility of the Law of Propagation of Light with the Principle of Relativity....................................................................................................................... 14
On the Idea of Time in Physics..................................................................................... 16
The Relativity of Simulatneity...................................................................................... 18
On the Relativity of the Conception of Distance .......................................................... 20
The Lorentz Transformation ......................................................................................... 21
The Behaviour of Measuring-Rods and Clocks in Motion........................................... 24
The Heuristic Value of the Theory of Relativity .......................................................... 29
General Results of the Theory ...................................................................................... 30
Experience and the Special Theory of Relativity ......................................................... 33
Minkowski's Four-Dimensional Space ......................................................................... 36
Special and General Principle of Relativity.................................................................. 38
The Gravitational Field ................................................................................................. 40
The Equality of Inertial and Gravitational Mass as an argument for the General Postule of Relativity .................................................................................................................. 42
In What Respects are the Foundations of Classical Mechanics and of the Special Theory of Relativity Unsatisfactory?............................................................................ 43
A Few Inferences from the General Principle of Relativity ......................................... 44 Behaviour of Clocks and Measuring-Rods on a Rotating Body of Reference ............. 46
Euclidean and Non-Euclidean Continuum.................................................................... 48
Gaussian Co-ordinates .................................................................................................. 50
The Space-Time Continuum of the Speical Theory of Relativity Considered as a Euclidean Continuum.................................................................................................... 52
The Space-Time Continuum of the General Theory of Realtivity is Not a Euclidean Continuum..................................................................................................................... 53
Exact Formulation of the General Principle of Relativity ............................................ 55
The Solution of the Problem of Gravitation on the Basis of the General Principle of Relativity....................................................................................................................... 57
Cosmological Difficulties of Newton's Theory ............................................................ 59
The Possibility of a "Finite" and yet "Unbounded" Universe....................................... 60
The Structure of Space According to the General Theory of Relativity....................... 62
Appendix I: Simple Derivation of the Lorentz Transformation (Supplementary to Section 11) .................................................................................................................... 63
Appendix II: Minkowski's Four-Dimensional Space ("World")(supplementary to section 17)..................................................................................................................... 67
Appendix III: The Experimental Confirmation of the General Theory of Relativity... 68
Appendix IV: The Structure of Space According to the General Theory of Relativity (Supplementary to Section 32)...................................................................................... 73
The present book is intended, as far as possible, to give an exact insight into the theory of Relativity to those readers who, from a general scientific and philosophical point of view, are interested in the theory, but who are not conversant with the mathematical apparatus of theoretical physics. The work presumes a standard of education corresponding to that of a university matriculation examination, and, despite the shortness of the book, a fair amount of patience and force of will on the part of the reader. The author has spared himself no pains in his endeavour to present the main ideas in the simplest and most intelligible form, and on the whole, in the sequence and connection in which they actually originated. In the interest of clearness, it appeared to me inevitable that I should repeat myself frequently, without paying the slightest attention to the elegance of the presentation. I adhered scrupulously to the precept of that brilliant theoretical physicist L. Boltzmann, according to whom matters of elegance ought to be left to the tailor and to the cobbler. I make no pretence of having withheld from the reader difficulties which are inherent to the subject. On the other hand, I have purposely treated the empirical physical foundations of the theory in a "step-motherly" fashion, so that readers unfamiliar with physics may not feel like the wanderer who was unable to see the forest for the trees. May the book bring some one a few happy hours of suggestive thought!
December, 1916 A. EINSTEIN