Enigma books
Xanthe Schneider is the American heroine of three e-thrillers about British naval intelligence from 1940-1 and the cracking of the Enigma code.
You can buy the complete novel in paperback or on kindle. Or you can buy the three parts seperately as short ebooks.
You may also be interested in the following ebooks and paperbacks about Enigma as non-fiction…
Alan Turing: Unlocking the enigma
Operation Primrose: U110, the Bismarck and the Enigma Code
Before Enigma: The Room 40 codebreakers of the First World War
Enigmas: Alan Turing and the codebreakers of the world wars (all three non-fiction titles bundled together for kindle)