Several years ago, before most of us paid much attention to the name Osama bin Laden, Reporter Jon Ronson spent a year following around a Muslim activist named Omar Bakri, who called himself bin Laden's "man in London." At first Ronson thought Bakri was on the "them" side of "us and them." But then Ronson got to know him, and changed his mind. After September 11, he had to change his mind again. Ronson tells his story, which includes excerpts from his book Them: Adventures with Extremists.