Breaking the Enigma cipher was not a do it once and its done kind of thing. The combination of all the various possible settings formed the "key" to decoding a message encoded using an Enigma machine. The Germans changed the key every day at midnight. So the code-breakers had to begin again. The techniques used changed several times during the war requiring changes in the process required to break the key. The book is about breaking the keys used by the German armies and air force. I've ordered another book about the naval codes.
After reading other books on the topic and era you may find that Welchman may have had a problem with humility. ( )

I haven't much to say about this book because I know I'm unable to finish it. The subject is compelling and interesting. The root cause of my lack of enthusiasm for this volume is two-fold.

1) I've read a lot more than one other book on the topic of Enigma and the personalities who worked at Bletchley Park.

2) All of them were better written than this one.

If you are a devotee of the subject, Welchman's extremely detailed but poorly constructed and rather dull narrative of this point and incident of the history of WWII may be your cup of tea. After all, he probably was the biggest mind and greatest hero for his dam-breaking thinking and solutions to the enigma of Enigma. Just not as well know as Turing probably because of the conventionality of his personality, a personality that is not enlivened on the pages of his memoir. ( )