Introduction

Einstein's great paper of 1905 on the special theory of relativity appears effortless, and as discussed in Chapter 16, he did not regard the formulation of the theory as a particularly ‘revolutionary act’. The route to the discovery of the general theory of relativity was very different. Whereas others had come close to elucidating the essential features of special relativity, Einstein was on his own and went far beyond all his contemporaries in his discovery of the general theory. How he arrived at the theory is one of the great stories of theoretical physics and involved the very deepest physical insight, imagination, intuition and sheer doggedness. It would lead to concepts barely conceivable even by a genius like Einstein – the phenomenon of black holes and the possibility of testing theories of gravity in the strong-field limit through the observation of relativistic stars. General relativity also provided for the first time a relativistic theory of gravity which could be used to construct fully self-consistent models of the Universe as a whole.

The history of the discovery of general relativity is admirably told by Abraham Pais in his scientific biography of Einstein, Subtle is the Lord … the Science and Life of Albert Einstein, which discusses many of the technical details of the papers published in the period 1907 to 1915. Equally to be recommended is the survey by John Stachel of the history of the discovery of both theories of relativity.