The book (Leo Marks : From Silk To Cyanide) gives a slightly different slant from most books of this type.

Heard the author on BookTV and was intrigued by the drama of his work, and at such a young age. Quite amazing!
I'm useless at codes -- most things mathematical for that matter, except music -- but the narrative itself is quite compelling I thought.

As you know from reading the book, Leo was the son of the owner of Marks & Co which was the subject of Helene Hanff's book "84 Charing Cross Road" later a movie with Anthony Hopkins, Judi Dench and Mel Brooks' wife, Anne What's-her- name.
"84" is the story of a New York writer and her real letters to and from the Marks & Co. bookstore manager as she sought and he found books for her over many years, post-WWII. You might want to borrow it from library after you finish "From Silk To Cyanide." A pleasant read. There was a follow-up book to "84 Charing Cross Road" but I can't recall the title off hand.