I am fairly familiar with all forms of secret writings, and am myself the author of a trifling monograph upon the subject, in which I analyze one hundred and sixty separate ciphers [THE DANCING MEN].

Because there are many ciphers which I would read as easily as I do the apocrypha of the agony column – such crude devices amuse the intelligence without fatiguing it [VALLEY OF FEAR].

Sherlock Holmes.

There’s a new book just out that may be of interest to members   – ‘The Agony Column Codes & Ciphers’ by Jean Palmer available in e-book or paperback from Authors on Line or Amazon.co.uk – it’s a compilation of over a 1,000 secret messages from various 19th century newspapers –  the very ones Holmes refers to in the above quotes.