Colossus : The Secrets of Bletchley Park's Code-breaking Computers, Paperback Book

Colossus : The Secrets of Bletchley Park's Code-breaking Computers Paperback

3.5 out of 5 (2 ratings)


At last - the secrets of Bletchley Park's powerful codebreaking computers.

This is a history of Colossus, the world's first fully-functioning electronic digital computer.

Colossus was used during the Second World War at the Government Code and Cypher School at Bletchley Park, where it played an invaluable role cracking enemy codes.

Until very recently, much about the Colossus machine was shrouded in secrecy, largely because the codes that were employed remained in use by the British security services until a short time ago.

This book only became possible due to the declassification in the US of wartime documents.

With an introductory essay on cryptography and the history of code-breaking by Simon Singh, this book reveals the workings of Colossus and the extraordinary staff at Bletchley Park through personal accounts by those who lived and worked with the computer.

Among them is the testimony of Thomas Flowers, who was the architect of Colossus and whose personal account, written shortly before he died, is published here for the first time. Other essays consider the historical importance of this remarkable machine, and its impact on the generations of computing technology that followed.


  • Format: Paperback
  • Pages: 480 pages, Various line drawings and 16pp black and white plate section
  • Publisher: Oxford University Press
  • Publication Date:
  • Category: British & Irish history
  • ISBN: 9780199578146



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Showing 1 - 2 of 2 reviews.

Review by

Only in the past few years has the story of the Colossus computers and their use to break the German's WW2 Tunny encoding machines come to light. Unlike the rather well known story of the Enigma machine, the Lorenz encoding machine (code named Tunny by the Brits) was more complex and required far more effort to break. The effort to understand the process and then build the machines involved some of the great mathematics minds like Alan Turing, but also a number of persons who have stay in obscurity due to the British Official Secrets Act. Sadly the book itself is a collection of articles by numerous people involved in various ways and so is greatly varied in focus, scope and level of detail Often the same informaiton, like how the Tunny machine worked, is repeated several times by different authors. It is a difficult story to follow and the difficulties are continued by numberous appendices that often don't have enough explainations unless you can go back into the narrative and find the corresponding information. I've given it three stars because while for the casual or even more dedicated WW2 reader this books is a real struggle, those truely interested in the subject will find a rewarding amount of information.

Review by

A very rich history of WW2 Codebreaking genii and their machines. Not an easy subject for most laymen but well worth slugging through to the very end. The book is a compendium written by a sizeable panel comprising for the most part the original codebreakers and their electronic engineering inventors. The appendices(12) are well worth penetrating. A mathmetician's delight if you are into statistics, linear algebra, linquistics and prime numbers. There is thankfully a good level of repetition as each author contributes his/her account of the methods employed. Enigma was but the first of the code breaker triumphs at Bletchley Park. The "Lorentz" machine is the main fish in this book and was known then as the "Tunnny Machine" The solution techniques to solve the encryption are well explored and the necessity for the Colossi machines is well established. A most interesting account is given of the daily lives as experienced within a country engaged to save its skin under very bleak and daunting conditions of total war. Clearly war is the cradleof invention and WW2 clearly propelled the west into the computer age that we take for granted in our lives today. This is a book that supports the belief thet victory was most improbable without the Colossi code breaking equipment first coming on-line. More detail on the value of the information garnered will need a separate volume yet to be written.

Also by B. J. Copeland