Our age is obsessed by the idea of conspiracy. We see it everywhere--from Pearl Harbor to 9/11, from the assassination of Kennedy to the death of Diana. In this age of terrorism, the idea of conspiracy can fuel radical or fringe elements to violence. The author, a journalist, sees a pattern among these inflammatory theories. They use similarly murky methods to insinuate their claims: they link themselves to the supposed conspiracies of the past; they...