In 1755 Essai sur la nature du commerce en général, written in French circa 1732 by Irish businessman and economist, Richard Cantillon, was first published anonymously in London, in the French language, some twenty-two years after Cantillon died in a fire in his London home; the fire was allegedly set by Cantillon's discharged cook.
"Cantillon was perhaps the first to define long-run equilibrium as the balance of flows of income, thus setting the foundations both for Physiocracy as well as Classical Political Economy. Cantillon's system was clear and simple and absolutely path-breaking. He developed a two-sector general equilibrium system from which he obtained a theory of price (determined by costs of production) and a theory of output (determined by factor inputs and technology). His work is quoted by Adam Smith in his Wealth of Nations.
"Although his work was well-known to the Physiocrats and the French school, Cantillon fell into obscurity in the English-speaking world until resurrected and popularized by William Stanley Jevons in the 1880s." (Wikipedia article on Richard Cantillon, accessed 01-14-2009).
"The Essai is far more than a mere essay or even collection of disconnected essays like those of Hume. It is a systematic and connected treatise, going over in a concise manner nearly the whole field of economics, with the exception of taxation. It is thus, more than any other book I know, the first treatise on economics. Sir William Petty's Political Arithmetic and his Treatise of Taxes and Contributions are wonderful books in their way, and at their time, but, compared with Cantillon's Essai, they are merely collections of casual hints. There were earlier English works of great merit, such as those of Vaughan, Locke, Child, Mun, etc., but these were either occasional essays and pamphlets, or else fragmentary treatises. Cantillon's essay is, more emphatically than any other single work, 'the Cradle of Political Economy' " (Jevons, Principles of Economics, 164, quoted by Friedrich Hayek, "Richard Cantillon", Journal of Libertarian Studies VII  221).