THE EMPEROR IN question is Napoleon Bonaparte, one of the most celebrated and exceptional military leaders in world history. And the year is 1809. La Grande Armée had won a series of brilliant military victories that had given Napoleon unprecedented control over most of Europe. Nobody, it seemed, could withstand his shock and awe tactics that exploited intense artillery fire and rapid cavalry charges.

Napoleon, however, was about to taste a rare defeat against a most remarkable opponent. This defeat was not on the battlefield but in that game of kings: chess. And to rub salt into Napoleon’s wounds, his opponent was not human but a machine known as the Mechanical Turk.