The Man Who Was Thursday by G.K. Chesterton

Gabriel Syme, recently made a philosopher-policeman, finds himself at a meeting for a group of anarchists headed by the enigmatic Sunday. He is unexpectedly made Thursday, and is involved in a plot to bomb the Czar and the President of the French Republic. However, before he was taken to the meeting, he was made to swear that he would not reveal the group to the police, and when he attempts to frustrate the plot himself the story grows increasingly fantastic.

Chesterton said, "You've got that eternal idiotic idea that if anarchy came if would come from the poor. Why should it? The poor have been rebels, but they have never been anarchists; they have more interest than anyone else in there being some decent government. The poor have sometimes objected to being governed badly; the rich object have always objected to being governed at all."
In this story the opposition comes from the seemingly innocent and stupid; and the friends are those who seem to be anarchists. Syme's world is continually turned upside down.