On June 5 1944, a courier from Britain’s Bletchley Park code-breaking centre interrupted a D-Day planning session and handed a top-secret message to General Dwight Eisenhower. After reading the slip of paper, the Supreme Allied Commander in Europe declared: “We go tomorrow.”
The message contained a decrypted German radio transmission from Adolf Hitler telling his top commander in France that the imminent Allied invasion in Normandy was a feint; the subsequent delay in redeploying German troops proved crucial in allowing Allied forces to secure their beachheads. The technology that enabled the decryption was the world’s first electronic programmable computer. Called Colossus, it was designed by Tommy Flowers, an unassuming English Post Office engineer.
That episode was the first example of a computer having a decisive impact on world history, Nigel Toon suggests in his sparky new book on artificial intelligence, How AI Thinks. But it was only a foretaste of what followed; in the subsequent eight decades, computers have become exponentially more powerful and have extended their reach into almost every aspect of our lives.