The American ENIAC is customarily regarded as the first electronic computer. In this fascinating volume, Jack Copeland rewrites the history of computer science, arguing that in reality Colossus--the giant computer built in Bletchley Park by the British secret service during World War II--predates ENIAC by two years. Until very recently, much about the Colossus machine was shrouded in secrecy, largely because the code-breaking algorithms employed during World War II remained in use by the British security services until a short time ago. 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. A must read for anyone curious about code-breaking or World War II espionage, Colossus offers a fascinating insider's account of the world's first giant computer, the great-great-grandfather of the massive computers used today by the CIA and the National Security Agency.