The notebook of Nazi code breaker Alan Turing, the inspiration for the Hollywood hit the Imitation Game, is set to go up for auction.

The 56-page manuscript, which features notes about mathematics and computer science, will be sold at Bonhams auction house in New York on April 13, and is expected to go under the hammer for at least seven figures, with a portion of the proceeds intended to benefit charity.

Turing was a British mathematician who cracked Germany’s war time communications code, bringing about an early end to World War II.

The notebook has never been seen in public and dates back to 1942.

One excerpt from Turing reads: “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 …”

Benedict Cumberbatch portrays Turing in Oscar-nominated film The Imitation Game.

Turing scholar Andrew Hodges said in a statement through Bonhams auction house that the notebook shows how Turing “remained committed to free-thinking work in pure mathematics.”

The Imitation Game is based on Hodges’ book, “Alan Turing: The Enigma.”