A rare manuscript by famed theoretical physicist Albert Einstein will be up for auction this week and it is expected to go for a steep price.

The item to be auctioned off in Paris on Tuesday is a 54-page manuscript handwritten by Einstein himself as well as his lifelong friend and colleague, Swiss engineer, Michele Besso, AFP News reported. It was written sometime between 1913 and 1914 and is estimated to fetch between two and three million euros, or about $2.3 to 3.4 million.

"This is without a doubt the most valuable Einstein manuscript ever to come to auction," Christie's said in a statement, as per AFP.

In a feature earlier in November, Christie's noted that Einstein and Besso had known each other since they were students, and the manuscript actually contains equations that eventually led to his "radical new picture of the universe."

Apart from a manuscript that's at the Albert Einstein Archives at the Hebrew University in Jerusalem, this is the only one surviving that contains the "genesis" of the famed theory of relativity.

Christie's noted that because of Besso the manuscript was preserved as Einstein was not the type to save the early drafts of his work. But as for Besso, he kept the documents safe in his home until his death in 1955.

The manuscript contains 26 pages that were handwritten by Einstein, 25 that were written by Besso, and three that were written by both.

Apart from being a key piece of history, the manuscript also shows a bit of the two men's "sense of personality," Vincent Belloy, a specialist at the Books & Manuscripts Department at Christie's Paris, said in the feature. For instance, Einstein's sheets "almost exclusively" contained calculations while Besso's also had some written notes in the margins.

"The manuscript isn't bound, and there are many different types of loose paper, so you get the impression of a working document that's full of energy, as if both men would grab the first page they could find to scribble their findings on," Belloy said.

Previously, other works of Einstein were also sold for hefty pricetags. In May, for instance, a letter in which he wrote the famed E=mc2 equation sold for $1.2 million, which is three times higher than the expected $400,000.

In 2018, another one of Einstein's letters was sold for over $100,000 in Jerusalem. That time, it was a letter he sent in 1928, wherein he discussed one of his "groundbreaking theories."

Albert Einstein

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