Albert Einstein (1879–1955), one of the foremost scientists and public figures of the 20th century, revolutionized our views of time and space, matter and light, gravitation and the universe.

The Einstein Papers Project is engaged in one of the most ambitious scholarly publishing ventures undertaken in the history of science. *The Collected Papers of Albert Einstein* provides the first complete picture of Einstein’s massive written legacy.

*The Collected Papers of Albert Einstein* series now covers Einstein's life and work up to his 46th birthday. It presents, as annotated full text, 400 writings by Einstein and 3,450 letters written by and to him. An additional 2,654 documents appear in abstract.

A unique resource: You can access our database of 80,000 records of all known Einstein manuscripts and correspondence and also search the full text of 2,000 digitized items.

100 years ago Albert Einstein submitted a paper to the Royal Prussian Academy of the Natural Sciences which contained what we today call the Einstein field equations: the new law of gravity that superseded Isaac Newton’s inverse square law of gravity. On the same day, 25 November 1915, that Einstein submitted said paper, his preceeding paper on Mercury's perihelion was published. Here, Einstein correctly calculated an anomoly in Mercury's motion that had remained an unsolved puzzle in the context of the Newtonian theory of gravity. The paper had been submitted only a week earlier in turn, but it did not yet contain the final gravitational field equations that would become the core of the general theory of relativity.

Ten days prior to his submission of the final field equations, Einstein wrote to David Hilbert that he was suffering from exhaustion and abdominal pains. His intense work on general relativity and poor nutrition caused by the ongoing war had clearly taken their toll on Einstein's health. Still, when Einstein submitted the field equations on 25 November 1915, he was aware that he had reached his goal: the discovery of a law of gravity more accurate than Newton's, consistent with the results of special relativity, and indeed a generalisation of the latter theory. From the very beginning of searching for this new law of gravity, Einstein took the lesson from special relativity that mass and energy are equivalent as one of his starting points; or rather the idea that both mass and energy have to produce gravitational fields. The main question was what the resulting gravitational fields would be represented by, what the "left-hand side" of the Einstein field equations would be, given that their "right-hand side" was mass-energy. 10-27-15