To many he is the greatest scientist who ever lived, but a unique collection of Albert Einstein's letters and papers has revealed a history of struggle and failure made worse by an apparently shaky grasp of math.
An archive which goes on sale in London next month with a price tag of US$1.5 million shows how after transforming physics and securing unprecedented celebrity status with his general theory of relativity in 1916, Einstein suffered years of frustration as he failed to top that with "a grand theory of everything."
The 15 manuscripts and 33 letters penned between 1933 and 1954 give a glimpse into a period in Einstein's life when he strayed away from mainstream physics and grappled with the most fundamental questions concerning the universe.
"At the time, a lot of his colleagues, the theoretical physicists, felt that he was completely off the beaten path and so they didn't really take him seriously," said Howard Rootenberg, of Rootenberg Books in California, who is handling the sale. Although manuscripts dealing with Einstein's earlier work and his social and political views are relatively common, the collection is unique in helping to document the latter half of his life, when he moved to Princeton University in New Jersey and embarked on a struggle to unite all branches of physics.
But his work in this period made very little impact on contemporaries and he never found his grand theory -- something physicists are still grappling with.
The archive was collected by Einstein's colleague Ernst Gabor Straus, a young mathematician whom the great physicist selected to help him during his Princeton years.
"A lot of people think of Einstein as a mathematical genius -- he wasn't," said David McMullan, a physicist at Plymouth University.
* 1879: Born in Ulm, Germany, March 14.
* 1901: Acquired Swiss citizenship and took a job in the Swiss patent office.
* 1903: Married Mileva Maric. The couple had one daughter and two sons.
* 1905: Published his paper on special relativity.
* 1914: Appointed director of the Kaiser Wilhelm Physical Institute and professor in the University of Berlin. Became a German citizen.
* 1916: Published his paper on general relativity.
* 1919: Marriage was dissolved. In the same year he married his cousin, Elsa Lowenthal.
* 1933: Left Germany because of the rise of fascism and moved to Princeton, New Jersey.
* 1940: Became a US citizen.
* 1945: After World War II he became a leading figure in the World Government Movement. He was offered the presidency of Israel, but turned it down.
* 1955: Died April 18.
Source: The Guardian
He said Einstein used Straus as he had used other mathematically gifted colleagues in his early career.
"Straus's mathematical virtuosity gave a framework to Einstein's intuitive vision of the universe," McMullan said.
He said it was fascinating to see breakthroughs not coming easily to Einstein.
"I do think it is interesting, the way you see him groping around. He's just trying anything. Here we see the greatest scientist who ever lived struggling and being honest about it," he said.
In one sequence of 16 letters Straus criticizes a line of inquiry that Einstein is pursuing and eventually persuades him to abandon it.
"It would take somebody with real balls to say to Einstein, `look, this is wrong,'" said Peter Coles, a physicist at Nottingham University.
The papers have never been studied because they have been held by Straus and his family since they were written. Einstein scholars were not even aware they existed until Straus's wife and son decided to put them on the market.
They tell the story of the two men's evolving thought process in the vain search for the unified field theory, as the grand theory was called.
Einstein hoped to unite the forces of gravity and electromagnetism under one theoretical framework, which would at the same time incorporate quantum mechanics. But the search turned out to be a series of blind alleys.