The American ENIAC is customarily regarded as having been the starting point of electronic computation. This book rewrites the history of computer science, arguing that in reality Colossus--the giant computer built by the British secret service during World War II--predates ENIAC by two years.

Colossus was built during the Second World War at the Government Code and Cypher School at Bletchley Park. Until very recently, much about the Colossus machine was shrouded in secrecy, largely because the code-breaking algorithms that were employed during World War II remained in use by the British
security services until a short time ago. In addition, the United States has recently declassified a considerable volume of wartime documents relating to Colossus. Jack Copeland has brought together memoirs of veterans of Bletchley Park--the top-secret headquarters of Britain's secret service--and
others who draw on the wealth of declassified information to illuminate the crucial role Colossus played during World War II. Included here are pieces by the former WRENS who actually worked the machine, the scientist who pioneered the use of vacuum tubes in data processing, and leading authorities
on code-breaking and computer science.

A must read for anyone curious about code-breaking or World War II espionage, Colossus offers a fascinating insider's account of the world first giant computer, the great great grandfather of the massive computers used today by the CIA and the National Security Agency.