Colossus Book Cover
Quote from Financial Times
Colossus: The Secrets of Bletchley Park's Codebreaking Computers

Reveals the incredible story of the world’s first large-scale electronic computer—in the words
of the codebreakers who built and used it. Featured on TV and radio, this book discloses information that was classified until very recently.

Additional chapters by Stephen Budiansky (author of Battle of Wits and Her Majesty’s Spymaster), Simon Singh (author of The Code Book and Big Bang), Michael Smith (defence correspondent for the Sunday Times and author of Station X: The Codebreakers of Bletchley Park), and others.

Ideal for the general reader. Published by Oxford University Press in their Popular Science Series.

About the book

“A superb production which reveals a remarkable and previously untold story. One of the very best books about Bletchley Park.” Peter Hilton, leading codebreaker at Bletchley Park

“This is a fascinating book about an incredible story. Much has been written about the breaking of the Enigma cipher, but this collection of essays does a terrific job of recounting the story of cracking the high-level Nazi ‘Geheimschreiber’ communications at Bletchley Park. It is largely written by those who were directly involved in developing this remarkable codebreaking technology, thereby paving the way for modern computing.” Simon Singh, host of the TV show The Science of Secrecy

“Cracking tale. This compelling compilation of essays reveals how cryptologists at Bletchley Park broke some of the toughest Nazi codes. The chance to read the words of unsung heroes like Tommy Flowers, the engineer whose team built Colossus.” New Scientist

“a multilayered, broad picture of Bletchley’s work and personalities” Telegraph

“first person accounts ... provide a wealth of colour” Guardian

“an engaging book ... essential reading” Nature

“the dramatic story of a project that changed the course of the Second World War. ... Colossus does evoke the intense atmosphere at Bletchley Park, the informality and excitement fired by the vital nature of the work, and the paralysing effect of the secrecy that surrounded the project both during and after the war” Times Literary Supplement

“Highly recommended. The human interest woven into the narrative should make it appealing to a broad audience.” Choice

“An outstanding, enjoyable book that belongs in your personal library and would also be a long remembered gift.” Cryptologia

“excellent, ground breaking book, highly recommended” Books-On-Line

“If you want an exhaustive account of codebreaking at Bletchley Park, this is surely the book for you.” BBC Focus

“admirable clarity ... high standard” Times Higher Educational Supplement

“absolutely fascinating”

ISBN 0-19-284055-X (Hardcover)

ISBN 0-19-957814-X (Paperback)



Thomas H. Flowers, architect of Colossus
Thomas H. Flowers

Flowers was speaking in his quiet, modest way (writes Jack Copeland). He was telling me about the giant electronic computer he had built for codebreaking during the war. The story was riveting. “There should be a book about Colossus”, I suggested.“A book about Colossus...”, he said softly, almost disbelievingly. His computer’s role in the Allied victory had been secret for so long. I began the search for the codebreakers who could provide the rest of the complex picture. People said “We can‘t talk about a lot of it—Official Secrets Act”. But then British Intelligence declassified a crucial wartime report: 500 pages of previously ultra-secret material. Suddenly doors opened and tongues loosened. More...