The publishing of "The Wealth of Nations" marked the birth of modern capitalism as well as economics. Oddly enough, Adam Smith, the champion of the free market, spent the last years of his life as the Commissioner of Customs, meaning he was responsible for enforcing all the tariffs. He took the work to heart, and burned many of his clothes when he discovered they had been smuggled into shops from abroad. Historical irony aside, his invisible hand continues to be a powerful force today.