Armed with information, experts can exert a gigantic, if unspoken, leverage: fear. Fear that your children will find you dead on the bathroom floor of a heart attack if you do not have angioplasty surgery. Fear that a cheap casket will expose your grandmother to a terrible underground fate. Fear that a $25,000 car will crumple like a toy in an accident, whereas a $50,000 car will wrap your loved ones in a cocoon of impregnable steel. The fear created by commercial experts may not quite rival the fear created by terrorists like the Ku Klux Klan, but the principle is the same.