Sooner or later, all talk among foreigners in Pyongyang turns to one imponderable subject. Do the locals really believe what they are told, and do they truly revere Fat Man and Little Boy? I have been a visiting writer in several authoritarian and totalitarian states, and usually the question answers itself. Someone in a café makes an offhand remark. A piece of ironic graffiti is scrawled in the men's room. Some group at the university issues some improvised leaflet. The glacier begins to melt; a joke makes the rounds and the apparently immovable regime suddenly looks vulnerable and absurd. But it's almost impossible to convey the extent to which North Korea just isn't like that. South Koreans who met with long-lost family members after the June rapprochement were thunderstruck at the way their shabby and thin northern relatives extolled Fat Man and Little Boy. Of course, they had been handpicked, but they stuck to their line.