Alan Turing Bletchley Notebook Sells For $1m
A notebook used by British World War Two codebreaker Alan Turing has sold for more than $1m (£682,000) at auction.
The 56-page manuscript was written when the mathematician was trying to break the Enigma code used by the Germans throughout the war.
It contains complex maths and computer science notations and is the only extensive Turing manuscript known to exist, according to Bonhams auction house in New York.
The sale price was $1,025,000 (£700,029).
Turing's notebook dates from 1942, when he and his team of cryptanalysts were at the code and cypher school Bletchley Park.
In one entry, Turing wrote about a complex calculus notation.
"The Leibniz notation I find extremely difficult to understand in spite of it having been the one I understood the best once!" he wrote. "It certainly implies that some relation between x and y has been laid down eg, y=x2+3x."
The sale also included a working German Enigma enciphering machine. The three-rotor device, manufactured for the German military in July 1944, sold for $269,000 (£183,000) .
Turing was prosecuted for being gay at a time when it was illegal in Britain. He was convicted of indecency in 1952 and agreed to undergo hormone treatment in a bid to eliminate his homosexuality as an alternative to imprisonment.
He died in 1954 of cyanide poisoning. His death was ruled a suicide although his family and friends believed it might have been accidental. The notebook was among the papers he left in his will to friend and fellow mathematician Robin Gandy.
The Imitation Game, starring Benedict Cumberbatch in the role of Turing, won best adapted screenplay at this year's Academy Awards.
Bonhams said the buyer wished to stay anonymous but added that part of the proceeds will be given to charity.
