I had been visiting war zones since the 1980s and had begun my journey into the world of the Special Forces before September 11, 2001, but the attacks galvanized me to write a book about how they are sent around the world into all kinds of unconventional conflicts to figure out what to do, with less shooting and more cleverness than one might imagine. Their specialty is terrorism, guerrilla warfare and counterinsurgency and all its variants. But at bottom, this is a book about a group of men who have entrusted me with their stories.

I encountered a lot of natural skepticism and wariness, and a well-founded wish to protect national security, but in the end my willingness to jump on the back of the Humvee, get dirty, stay quiet and pay attention led the men on the teams to tolerate my presence as they went about their missions. It is a credit to them that they have agreed to share their stories despite the obvious dangers so the institution and way of life could be appreciated by Americans.