circa 1765:  Scottish political economist and philosopher Adam Smith (1723 - 1790). His 1776 treatise 'An Inquiry into the Nature and Causes of the Wealth of Nations' marked the beginning of modern economics. Smith was born in Kircaldy and studied at Edinburgh University and Oxford before lecturing in Edinburgh where he met his lifelong friend David Hume who greatly influenced his work. He held posts as Professor of Logic and Professor of Moral Philosophy at Glasgow University before resigning to become a personal tutor.  (Photo by Hulton Archive/Getty Images)