Hundreds of movies and thousands of books have been written about the heroes of World War II. For dozens of years, however, few people knew about one of the greatest heroes of the war—a mild-mannered, eccentric mathematician from the University of Cambridge.

This man, an undeniable genius whose later life was plagued by controversy and tragedy, probably played a greater role in the eventual Allied victory than anyone else. Until quite recently his contribution to the war effort was barely recognized. Everyone’s heard of Churchill, Eisenhower, Montgomery, Patton and even de Gaulle, but far fewer have ever heard of Alan Turing. This is his incredible story.