What do you get when you cross a Jehovah’s Witness with a Unitarian?

Somebody who goes from door-to-door for no reason.

I found this joke in P. J. O’Rourke’s new book On The Wealth of Nation. It is an excellent synopsis and interpretation of Adam Smith’s Tome.  O’Rourke writes in a humorously expository style that makes even the dense writing of someone like Smith understandable and relevant.
Simon