How Einstein Lost His Bearings, and With Them, General Relativity

Albert Einstein released his general theory of relativity at the end of 1915. He should have finished it two years earlier. When scholars look at his notebooks from the period, they see the completed equations, minus just a detail or two.

“That really should have been the final theory,” said John Norton, an Einstein expert and a historian of science at the University of Pittsburgh.

Source: quantamagazine.org