I got the book and couldn't put it down. Luckily when I got to the contest at the back I found myself with a couple of weeks of summer holidays with Pascal and my 286 and no internet connection.

I cracked the manual ciphers with computer programs. I started on the Engima cipher, but did not create an accurate Enigma machine (the drawings in the book were incomplete and I didn't know that and had no internet access).

A couple of years ago I chanced upon the book again and set about solving the Enigma part. https://williamedwardscoder.tumblr.com/post/145830743193/my-...

Fond memories! :D

The book is warmly recommended.