For most of the 140 years since it was named, the disorder known as burning man syndrome has operated in near-total obscurity. Even today it afflicts perhaps 200 to 500 people in all of North America and a few thousand worldwide. Until about three years ago, essentially all medical knowledge about it was contained in its name, erythromelalgia, which translates as "painful red extremities." Few doctors knew of it, only a handful had seen it, and none knew what caused it or how to treat it. At any given time, the few thousand people who had it suffered its torment--searing heat in the feet and lower legs and sometimes in the hands--without understanding why. Most thought they were completely alone.