Masterly .. I commend the book to both the professional and the general reader - Bletchley Park veteran Donald Michie

read Gannon to feel the collective power of human minds harnessed to the cause of defending our freedom

Colossus tells of the heroic efforts of the inventors and mathematicians [who] received no recognition for decades

A fascinating tour through the history of Colossus for the general as well as the technical reader

Gannon's book contains a mass of utterly fascinating and largely unknown material about an immensely important wartime project

In 1940, almost a year after the outbreak of the Second World War, Allied radio operators at an interception station in South London began picking up messages in a strange new code. Using science, maths, innovation and improvisation Bletchley Park codebreakers 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 codebreakers 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.

2007-12-03 The best "BP" book yet

Perhaps it is easier for a telecommunications engineer turned computer software engineer to read but I found the book to be compelling. The book is not only technically impressive, it rings true in the portrayal of the characters and their relationships. I think only the Post Office Engineering Department, later the P.O. Telecomms Business could have produced Tom Flowers. I worked with many like him, engineers with the intuitive flair necessary to create complex systems who entered the business at the very bottom and rose through it by merit.