Colossus: Bletchley Park's Greatest Secret

by Paul Gannon

In 1940, almost a year after the outbreak of World War II, Allied radio operators at an interception station in South London began picking up messages in a strange new code. Using science, math, innovation, and improvisation, Bletchley Park code breakers worked furiously to invent a machine to decipher what turned out to be the secrets of Nazi high command. It was called Colossus. What these code breakers didn't realize was that they had fashioned the world's first true computer. When the war ended, this incredible invention was dismantled and hidden away for almost 50 years. Paul Gannon has pieced together the tremendous story of what is now recognized as the greatest secret of Bletchley Park.

Genres: History, Nonfiction, War, Technology, Military Fiction, World War II, Military History

505 pages, Kindle Edition

First published January 10, 2006

Reviews

[Grant · Rating 5 out of 5]

Excellent history. History of the event, the invention of Colossus, but more, a history of signal interceptions, computing theory, general WWII history, this book covers a lot of ground. It's a great read.

[Alastair Chisholm · Rating 4 out of 5]

Engrossing, highly detailed and fascinating account of a period of history that until really very recently was still hidden away. The book cuts through the myths of Bletchley Park and shows an astonishing group of people working on seemingly impossible tasks every day.

The first myths to fall are to do with Turing. Not that the author has anything bad to say about him; but he barely features. The book quotes one other history that reports "Turing invented the Colossus computer to solve Enigma", pointing out that it's almost entirely untrue - he didn't invent Colossus, he didn't even work on it, and it was never used to solve Engima. Colossus was used to solve an altogether different - and arguably much harder - decryption problem, and was the final link in an incredible chain of technical innovation and human obsession.

The amount of detail is sometimes overwhelming, and I freely admit I couldn't follow all the maths! But it is engrossing and, thanks to the author's focus on the characters involved, often funny. An excellent read.

[Lukerik · Rating 4 out of 5]

A history of codebreaking from the 19th Century to the end of WWII. It focuses on Bletchley Park and Colossus. Original research. Looking at Gannon’s sources there’s some really dull stuff, but somehow he’s managed to turn them into something really interesting. It’s often technical. Not tables-of-mathematics technical, but still a challenge. Codebreakers will have no problem following along, but I lost sight of the minutiae somewhere along the way. It helps that he opens with 19th Century naval signals using hatches because my brain could follow the switch to electronics with the Vernon cypher. Beyond that, well there’s a reason I’d be working in a supply depot if there was a war. It would have helped if the book had pictures.

Particularly good was his setting of Colossus in it’s historical context. Not to understate the achievement, but it’s been invented with vacuum tubes but not in a vacuum haha. Would recommend to anyone interested in the history of computers or if you want to see WWII from a different perspective.

[Antoine · Rating 5 out of 5]

Read when it came out right after visiting Bletchley Park. Almost made all the stories about Enigma less interesting. Really enjoyed it.

[Arthur Ryman · Rating 4 out of 5]

A Detailed Account of How the Lorenz Cipher Was Broken

Lots of technical, historical, and mathematical detail. Written in a dry, factual style. Could have been better edited and ordered. I would have appreciated a more chronological structure, unfolding like a story follow the course of the war.

[David · Rating 4 out of 5]

Detailed book

This is a very detailed book covering code breaking during the war. It is not just about Colossus but about the wider code breaking of the non morse code (not the enigma code). It is a very interesting book but not an easy read.

[Richard Anton · Rating 5 out of 5]

Very detailed account of work around Colossus during WW2.

[Wyl Young · Rating 4 out of 5]

Interesting and informative. Sometimes repetitive and too detailed; but over-all an enjoyable read for one interested in WW II or codebreaking/ciphers.

[Peter Hiller · Rating 4 out of 5]

This book is an interesting look at colossus and Bletchley park in general. The author seems to be very happy with their ability to their hands on information on colossus that others haven't. I'd guess that this would make a good source book for further analysis, but in itself the writer just didn't have that spark.

I was hoping for more technical analysis on the breaking of collosus that you normally get. This one fulfilled that to a degree, but it wasn't as detailed as I hoped. One place where it was very interesting was that it gave alot of extra information on the capture of the data and who was doing it, The post office stories was interesting as a part of the story I'd never really heard about before, I knew flowers worked for them, but their part in capturing the cyphers I wasn't even aware of.

All in all, a decent book, but not a great one

[Raj · Rating 3 out of 5]

This book, about the history of codebreaking during the second world war, didn't really grab me, I'm afraid. The eponymous machine itself was barely mentioned until almost half way through and it didn't seem to have focus. That was the point, I suppose, it was providing an overview, but it was never really able to hold my interest properly.

It was interesting to learn about the different types of enciphering that went on during the war, though, and the fact that the British government, when it eventually got around to releasing the papers about them, went out of its way to downplay Colossus and the Ultra code by playing up Enigma.

[Brian Page · Rating 4 out of 5]

The story of Enigma and the cracking of the Nazi Morse code transmissions is relatively well known. What is far less known is the British decryption of the German teleprinter communications which carried the far more important strategic discussions of the German war planning. Paul Gannon’s absolutely masterful account corrects this imbalance. In terms of intellectual achievement, Colossus was the equal of the Manhattan Project or the Rad Lab. This is a must-read for anyone interested in WW II history, statistics, or computing.

[Stuart · Rating 4 out of 5]

Using the Colossus computer the wartime British secret agencies were able to decode German encrypted telegraph messages. More secret than the Enigma, the machines and techniques involved may have been used into the Cold War period to decode Soviet messages.

Cryptology enthusiasts and historians should read this tome once. To understand exactly how they did it, you'll need to read it twice or more. You probably won't read it twice.

[Chris Shepheard · Rating 3 out of 5]

A very interesting subject but not dealt with in an easily readable way. The subject is extremely complicated and even now some of the material needed to complete the picture is still classified.

Some areas of the book go into great detail but the supporting illustrations don't appear alongside the explanatory text. Rather they are in the appendices at the end of the book making the examples difficult to follow.

Nonetheless this is a very thorough work that has a worthwhile story to tell.

[Phil · Rating 4 out of 5]

A detailed and interesting book on the interception and breaking of the German high level teleprinter messages. This is distinctly different from the breaking of the Enigma generated Morse code transmissions, although both took place at Bletchley Park, and some of the senior people were involved in both operations.

[Gerry · Rating 3 out of 5]

A book about the use of computers in code cracking during the second world war. It is non fiction and not well written at all BUT worth struggling with as it a deeply fascinating subject covered in finicky detail. A techies book but even then not well written.

[Heikki · Rating 5 out of 5]

Now, if you are interested in Bletchley Park, and have read your fill of the early tools on Enigma, you really should take this one up. It is a fascinating account of the operation that produced Colossus, the first true binary computer.

[Simon · Rating 4 out of 5]

Gives wonderful insight into this particular aspect of the war. Reading some chapters on Kindle was a challenge as they repeatedly make use of the Annexes.

[Justin Thomas · Rating 4 out of 5]

I thought the book has interesting information about code breaking, but is defuse with references to different chapters and is protracted.