Hi! Yes it is called 'Between Silk and Cyanide'. I work in IT in information security so I thought it would be good as it's sort of about the birth of encryption. I am so glad you have read it - did you notice there are loads of typing errors in the text and is it relevant?!! I think I should have noted them down from the start as I am convinced it is a message in code!! Am I mad?

I fancy going to Bletchley Park now - there is a visitor centre there. Have you been?