Einstein: What is the Theory of Relativity?

What is the Theory of Relativity? According to the Man Himself? This short article was originally written by Albert Einstein at the request of The London Times, in 1919, and it was intended for the general audience. If you are interested in getting a general overview, and the historical context, regarding Einstein's relativity, then this is the best introduction (10 pages). (Despite the somewhat ambiguous title, however, this article will not teach you the theory of relativity. For that, you will need to consult a slightly more advanced reference.) Einstein published his two seminal papers on special relativity in 1905, and he published his field equations for gravity (now known as Einstein's field equations) in 1915, which was viewed as the completion of the theory of general relativity. One of the most important predictions of his theory was bending of light in a strong gravitational field. This was confirmed by the English expedition led by Sir Arthur Eddington in 1919, during the solar eclipse, which made Einstein an instant celebrity. This newspaper article was published after Eddington's public announcement of this rather exciting and historical event. (It was right after the end of WWI.) It was originally written by Einstein in German, and both the German and English-translated versions are now in public domain. This short booklet attempts at a new translation to give a somewhat clearer account of what Einstein wanted to convey in his original writing. It is the BEST high-level account of the development of relativity, by Einstein himself! A completely new English translation - 2024! Note: This article, "What is the Theory of Relativity?", by Einstein and the Translator's notes are also included in the book, "Einstein's Seven Essays on Relativity, Geometry, and Scientific Methods" (2025).