IT is one of the most chilling images to emerge from the horror that has become, simply, 9/11. Against the steel-and-glass background of the World Trade Center, a man falls headlong 1,300ft to the street below. While pictures of the Twin Towers billowing smoke and flames will remain the most enduring image of the terrorist attacks, this one man's dying moments somehow humanise the toll of New York's darkest day. And yet, as famous as the image is, the man's identity has remained a mystery. Until now. Five years after the horror of September 11, 2001, the falling man has...