Notebook owned by the father of computer science to be auctioned The journal that Alan Turing used to jot down his thoughts on a universal language was later turned into a dream diary by one of his students By Charlotte Burns Alan Turing The only manuscript by the tragic British mathematician and wartime code-breaker Alan Turing still in private hands will be auctioned next week, 13 April, at Bonhams New York. The handwritten document dates from the Second World War, around 1944, and is estimated to sell for around $1m, a spokeswoman says. The notebook contains Turing’s observations on the work of other mathematicians, revealing his thought processes as he grappled with a “topic of profound importance: the development of a universal language; something that was to be at the core of modern computer science”, according to the auction catalogue. Turing worked on one of the world’s first recognisable computers, the Manchester Mark 1. He is also credited with laying the foundations for the study of artificial intelligence and for ideas that sparked chaos theory. Turing is best known as a wartime hero for his work on successfully decoding messages encrypted by the German Enigma machine. On the outbreak of war, he worked at the British code-breaking centre, Bletchley Park, inventing a device known as the Bombe that deciphered German messages intercepted by the Allies. But, disgraced by a conviction for “gross indecency” for homosexuality in 1952 and an enforced chemical castration, Turing committed suicide in 1954. The UK government formally apologised to Turing in 2009. The then-Prime Minister Gordon Brown said: “He truly was one of those individuals we can point to whose unique contribution helped to turn the tide of war. The debt of gratitude he is owed makes it all the more horrifying, therefore, that he was treated so inhumanely.” Turing’s story was turned into a movie last year, “The Imitation Game”, starring Benedict Cumberbatch. This notebook has remained private for quirky reasons. Turing willed his mathematical books, articles and manuscripts to the British logician and mathematician Robin Gandy, who had studied under Turing at Cambridge University. In 1977, Gandy donated everything to an archive at King's College, Cambridge—with the exception of this notebook. Gandy had filled its blank pages with his own dream diary, and wished the rather personal contents to remain secret, which they did until after his own death in 1995.