Partially in color, according to the historical original document
Format 6 x 9 "
We did our best to make the original material as readable as possible while preserving its original charm. We hope you enjoy reading this manuscript, which represents a real piece of history.
In late 1940, Alan Turing wrote a report describing the methods he and his colleagues at Bletchley Park used to decrypt the German Enigma cipher machine. At Bletchley this report was known as "The Professor's Book".
A copy of the manual was published in April 1996 under the title "Turing's Treatise on Enigma" thanks to the declassification by the American National Security Agency.
A much better copy of the original from the (British) National Archives, box HW 25/3, has been published below. This publication also revealed the title that had been lost in the American copy: Mathematical Theory of the ENIGMA Machine.
(Although, strangely enough, the report doesn't actually contain any mathematical theory.)
