Albert Einstein (1879-1955) and Marcel Grossmann (1878-1936).

'Entwurf einer verallgemeinerten relativitätstheorie und einer Theorie der Gravitation.' Offprint from: Zeitschrift für Mathematik und Physik, Vol. 62, Heft 3, pp.225-261. Leipzig: B.G. Teubner, 30 January 1914.

Hans Albert Einstein’s copy of his father’s offprint of the first 'outline' (Entwurf) of a fully developed theory of General Relativity, co-written with his friend and classmate, Marcel Grossman. This joint paper is, in fact, already very close to the final version of the general theory of relativity as published in November 1915, and constitutes an enormous advance over Einstein's first attempt at a generalized theory of relativity and theory of gravitation, published in 1912. The crucial breakthrough was Einstein's recognition that the gravitational field should not be described by a variable speed of light (as attempted in his 1912 theory), but by the so-called metric tensor, a mathematical object of 16 components, 10 of which independent, that characterizes the geometry of space and time. In this way, gravitation is no longer a force in space and time, but part of the fabric of space and time itself. Einstein had turned to Grossmann for help with the difficult and unfamiliar mathematics.

Any theory of the gravitational field can be divided into two parts, one describing how the gravitational field affects matter, the other describing how matter in turn generates gravitational fields. As far as the first is concerned, the Einstein-Grossmann theory of June 1913, as published here, is identical to the general theory of relativity in its final form. The difference between the two theories concerns only the second part. The theories of 1913 and of 1915 use different field equations for the metric field, which represents the gravitational field in these theories. (Field equations determine the gravitational field produced by a given distribution of matter.) During his collaboration with Grossmann, Einstein had considered field equations very similar to those he eventually arrived at in November 1915. From a purely mathematical point of view, these equations were the natural candidates, but at the time, Einstein convinced himself that they were unacceptable from a physical point of view. Instead, he chose a set of equations-now known as the Einstein-Grossmann equations or the 'Entwurf' field equations. This early struggle to find suitable field equations is documented in the Zurich notebook of late 1912/early 1913, the only other extant research manuscript of this period. Schlipp 53; Weill 58a (separate offprint giving a date of 1913).

Octavo (244 x 163mm). Original printed wrappers, marked 'Sonderabdruck'. Provenance: H.A. Einstein (1904-1976; front wrapper with his stamp with Berkeley CA address, numbered ‘32’ in red biro, and dated '30.I.14' in pencil).

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