Alan Turing’s lost notebook, in which he worked on the foundations of modern computer science, was sold for a whopping $1,025,000 at the Fine Books & Manuscripts Sale at Bonhams, which took place yesterday in New York, Art Fix Daily reports.

The sum doesn’t come as a surprise. When the auction of the notebook was first announced last January, its price estimate was exactly $1 million (see Buy Codebreaker Alan Turing’s Secret Manuscript for $1 Million). A part of the proceeds from the sale will be donated to charity.

The 56-page document was penned by Turing in 1942, while working at the intelligence center Bletchley Park on breaking the Nazi’s Enigma Code. Turing’s decoding was instrumental in the Allies’ defeat of Nazi Germany in World War II.

According to Bonhams New York, it is almost certainly the only extensive hand-written document by Turing in existence.

The manuscript—an unassuming notebook from a stationers in Cambridge—was among the papers that Turing bequeathed to his friend and fellow mathematician Robin Gandy.

Turing committed suicide in 1954, while undergoing a compulsory hormone treatment to “cure” homosexuality, imposed on him as an alternative to prison.

His groundbreaking research and tragic demise have been recently portrayed in the film The Imitation Game, in which Benedict Cumberbatch played the computing genius, earning an Academy Award nomination.

“This is a wonderful result and a fitting testament to Alan Turing’s impact and legacy,” Bonhams’s Cassandra Hatton said of the sale in a statement.

Turing ephemera is definitely having a moment (see Hollywood Collectors Snap Up Nazi Code-Breaker Alan Turing’s Papers). A rare 3-rotor German Enigma enciphering machine also changed hands during the same auction yesterday, fetching $269,000.