Between Silk and Cyanide: A Codemaker's War, 1941-1945 by Leo Marks

Between Silk and Cyanide was a fascinating look into the codebreaking department of the SOE (Special Operations Executive WWII).  

Leo Marks (his father owned 84 Charing Cross Road, the antiquarian bookshop made famous by Helene Hanff) was twenty-two when he entered SOE as a cryptographer.  

His unconventional and singular approach to coding led him to confront his superiors and eventually, to change much about the codes given to agents.  Undoubtedly brilliant, Marks also has a smugness and self-indulgence in his writing that can be irritating, but his concern for the agents is genuine, and he was willing to stand his ground in order to provide the agents the best codes and as much support as possible.

His initial change was the use of poem codes.  First he exposed how easy it would be for the Germans to break a code using a traditional poem, then he began having agents write their own poems or gave them one of his own original poems for the purpose.  His own poems were often crude and bawdy.  His most famous and touching poem, however, was given to Violet Szabo, one of the most highly regarded and tragic SOE agents:

The life that I have
Is all that I have
And the life that I have
Is yours.
The love that I have
Of the life that I have
Is yours and yours and yours.
A sleep I shall have
A rest I shall have
Yet death will be but a pause.
For the peace of my years
In the long green grass
Will be yours and yours and yours.

The title is an interesting point, Between Silk and Cyanide.   Marks spend much time and effort getting codes transferred to silk which could be easily concealed clothing lining.  First he had to battle to get his idea approved, then find financial aid, the silk itself, and a means of photographing the codes.  The idea was that after use, each code could be torn or cut from the silk.  The silk one-time pads prevented some agents from resorting to the cyanide pills they carried in case of capture.


Just one other way in which Marks contributed was in the area of indecipherables.  Prior to his efforts, agents were asked to resend any message that was indecipherable, a terrible risk for the agent, and a loss of time for any action needed.  Marks went to the decoding department and spoke to the women impressing on them the importance of somehow deciphering the original message.  The agent may live or die by their efforts.

Thereafter, the women sometimes made thousands of efforts to decipher one indecipherable message, reducing the number of indecipherables by approximately 80%.  

The book is over 600 pages long, and there is no way to cover all of the interesting information it contains:  the Dutch situation, the famous agents, Marks' efforts to make inroads with the Free French, the one-time pads, his concern not only about deciphering indecipherables, but about reducing the number of them...on and on.

Young Marks was a genius, and his innovations made a huge difference in the safety of those operatives behind enemy lines. His sometimes irritating wit was easy to overlook because of his dedication to the agents in the field.

Nonfiction.  2000.  624 pages.