The Hut Six Story

The men and women of Bletchley Park, who repeatedly broke German military cyphers throughout the Second World War, made an incalculable contribution to the allied success. This book, written by one of the code-breakers provides a fascinating insight into the process.

Despite the core subject, this is not really a book about cryptography, but about how to manage people and technology to solve complex, important problems. Welchman was the "glue" between the pure ideas men like Alan Turing, and the code-breaking production line.
His talents were clearly in building the organisation, and liaising between the different parties so that interception, decoding, understanding and using the intelligence became a repeatable success.

Welchman’s insights into British wartime society and bureaucracy are keen and frequently very humourous. Many of his insights are equally applicable today, in business as well as military circles. For example an individual’s promotion, prestige and salary should not depend solely on the number of subordinates.

Although he was very modest about it, it is clear that Welchman was no mean cryptologist himself. The book does attempt to explain several of the ways in which Enigma was cracked, but I found the primarily verbal explanations difficult to follow. However, this doesn’t prevent an understanding of the principals, and how different methods were applied at different points during the war.

The book does have some limitations. Because he was not personally involved, he explicitly refuses to discuss the effort focused on the German naval codes so important to the Battle of the Atlantic, and generally says little about the use of the intelligence information. Sadly, the current edition of the book omits much of Welchman’s advice on the analysis of battlefield communications, and how to keep such communications secure. However, one observation has been retained – it was a fundamental mistake to believe Enigma was secure simply because of the enormous computing power required for a brute-force attack. This should perhaps be noted in our Internet age, when so much depends on the assumed difficulty of factoring large numbers.

If I have a criticism of the book, it’s the rather poor production in places, with very faded photographs and occasionally blurred text. Figures are sometimes absent when they are most needed, e.g. when first explaining the Enigma machine. I read this book having only recently attended an excellent lecture and actually seeing an Enigma – otherwise I would have struggled at such points.

Nonetheless this is an excellent, insightful and inspiring book, containing a range of lessons relevant today, and I thoroughly recommend it.