A notebook revealing Alan Turing’s mind-boggling calculations as he battled to crack the Enigma code during World War II is expected to fetch £600,000 at auction.
The book – which has never been seen in public before – dates from 1942 when he was working at Bletchley Park to break the Nazi code.
It contains 56 pages of handwritten workings and provides a remarkable insight into the thought process of a genius.
In the pad, bought in Cambridge, Turing writes about how extremely difficult it is to understand the Leibniz notation.
He wrote: “The Leibniz notation I find extremely difficult to understand in spite of it having been the one I understood the best once! It certainly implies that some relation between x and y has been laid down eg, y=x2+3x?”
The colourful covered notebook is made up of complicated mathematical workings and is split into three parts – with the first two sections consisting of Turing’s maths notes.
The third part belongs to Robin Gandy, a friend and fellow mathematician, who was handed the notebook by Turing.
Gandy, who donated most of Turing’s papers to the archive at King’s College, Cambridge, kept the notebook and wrote deeply personal dream sequences in it at the request of his psychiatrist.
The notebook’s now anonymous owner has decided to sell the notebook on April 13 at Bonhams’ Fine Books and Manuscripts sale in New York.
It is expected to fetch a staggering #620,000 ($1 million) with a portion of the proceeds going to charity.
Andrew Hodges, a leading Turing scholar, said: “Alan Turing was parsimonious with his words and everything from his pen has special value.
“This notebook shines extra light on how, even when he was enmeshed in great world events, he remained committed to free-thinking work in pure mathematics.”
Turing is regarded by many as one of Britain’s most talented mathematicians.
But despite playing a starring role in World War 2, he was later treated as a pariah.
In 1952, he was prosecuted for homosexual acts and, to avoid jail and ‘cure’ his homosexuality, he was chemically castrated.
As a result of his conviction, Turing lost his security clearance so could no longer continue his code-breaking.
He committed suicide two years later and it wasn’t until 2013 that he was pardoned.
A biopic on the tragic genius was last week nominated for eight Oscars with Benedict Cumberbatch in the running for the Best Actor gong.
Cassandra Hatton, senior specialist in Fine Books and Manuscripts and the History of Science at Bonhams, said: “This manuscript dates from the time when Turing was engaged in the crucial task of breaking the Enigma Code.
“Its mathematical content gives an extraordinary insight into the working mind of one of the greatest luminaries of the 20th century.
“This is quite simply one of the most extraordinary pieces I have ever had the privilege to handle.”