The highly productive habits of Alan Turing

June 23 marks the 100th birthday of Alan Turing. If I had to name five people whose personal efforts led to the defeat of Nazi Germany, the English mathematician would surely be on my list. Turing’s genius played a key role in helping the Allies win the Battle of the Atlantic—a naval blockade against the Third Reich that depended for success on the cracking and re-cracking of Germany’s Enigma cipher. That single espionage victory gave the United States control of the Atlantic shipping lanes, eventually setting the stage for the 1944 invasion of Normandy.