Aided by more than 200,000 FBI interviews, the report is the official accounting of September 11, 2001. It's an exhaustive examination of what happened leading up to and during that day when Muslim extremist hijackers commandeered four planes and flew them into New York's World Trade Center Towers, the Pentagon in Washington, and a field in western Pennsylvania.
But buried at the back of the nearly 600-page report are 1,742 footnotes -- many of them stories of people who, like Duffy, came face-to-face with the horrors of 9/11.
Those footnotes illustrate how ordinary Americans responded that day.
"I always thought the most interesting part of the whole report was in the footnotes," said John Raidt, one of the primary 9/11 commission report investigators who now works as a senior fellow at the Atlantic Council.
"What struck me, particularly ... was a sense of responsibility," he said. "There was so much guilt shared by so many people that had nothing to feel guilty about.
"Ironically, at the time I think that feeling wasn't shared so deeply -- and I want to be fair -- as you go up the rungs."
CNN spoke to eight of the men listed in the commission report's footnotes -- the ticket agents, the pilot on alert to shoot down a passenger jet, the maintenance worker who took a phone call from a flight attendant on one of the ill-fated jets.
These people woke up on 9/11 expecting a routine day. Ten years later, the guilt over being unable to avert the disaster still looms for some.
The order to shoot
As he looked at the clear blue sky over Cape Cod on the morning of September 11, 2001, Lt. Col. Tim Duffy felt frustrated.
Duffy -- who was stationed at Otis Air Base but worked as a civilian pilot for United Airlines -- had flown the day before, so it was unlikely he'd get to go up in the skies on such a beautiful day.
Then, he got the call that would change his life forever.
