When the 250th anniversary of his birth was celebrated quietly in 1973, Adam Smith was, by and large, an afterthought, at least in the public realm of newspapers and magazines. The Organization of Petroleum Exporting Countries was in the saddle, and 20 years of extraordinary worldwide growth were abruptly ending, for reasons that are still not well understood. Economics, at least as Smith had framed it, was widely said to have somehow lost its explanatory snap.

This month the 200th anniversary of Smith's death is being celebrated in Scotland with a good deal more grandeur. First it was a band of businessmen and politicians who flocked to Edinburgh for a Wealth of Nations 1990 symposium that its organizers, the World Business Forum, billed as ''the most important conference to be held anywhere in the world this year.'' It ended last week, about the same time as the Group of Seven economic summit in Houston.

This week it is the economists' turn to make the pilgrimage to Scotland. No fewer than 11 Nobel laureates are invited on a two-day program to honor the man who put the concepts of the free market and the ''invisible hand'' at the center of modern technical economics, the scholar who wrote: ''Where competition is free, the rivalship of competitors ... obliges every man to endeavor to execute his work with a certain degree of exactness. ... Rivalship and emulation render excellency, even in the mean professions, an object of ambition, and frequently occasion the very greatest exertions.''

The differing atmospheres surrounding the two meetings are instructive. Led by former British Prime Minister Edward Heath, Salomon Brothers's John Gutfreund, investment banker Lord Roll of Ipsden, HUD Secretary Jack Kemp, and others, the celebrants of the Wealth of Nations tended to be veterans of the recent battles of the global Turn to the Right, fought during the 1970s and 1980s. Uppermost in the minds of participants seemed to be the sudden tilt toward markets of the Eastern European economies.

The invited economists, on the other hand, had made a much longer march to Smith's grave at Canongate Kirk. They included Paul Samuelson, who as a young man began the encoding of economics in mathematical language at Lincoln Labs in Cambridge; Laury Klein, the father of econometric modeling, who began his career about the same time as a committed Marxist; and Maurice Allais, who spent his war writing up an impenetrable tract on the price system that went virtually unnoticed outside of France until he was awarded the Nobel Prize in 1988.

Now, with the economies of the Soviet Union and Eastern Europe collapsing at the end of a disastrous 70-year experiment in central planning, both politicians and philosophers are rushing to stand alongside Adam Smith, the man who identified competition as a natural and desirable state of affairs, who analyzed its ins and outs with dry wit and memorable skepticism.

Who was Adam Smith? The son of a customs inspector born in 1723, Smith took quickly to university life at 14, traveled widely on the continent, became an admirer of Isaac Newton, a friend of David Hume and, with the publication of ''The Theory of Moral Sentiments,'' a principal of the Scottish enlightenment. As a fellow of the Royal Society in London and a private tutor in Paris, he spent his evenings with the best minds of his generation, including Samuel Johnson, Edmund Burke, Edward Gibbon and Voltaire. When ''An Inquiry into the Nature and Causes of the Wealth of Nations'' was published in 1776, it was at first taken simply to be a massive critique of mercantilism, the system of close governmental regulation of economic and social affairs.

Knocking mercantilism was one thing. Smith, however, offered something to put in its place, a ''system of natural liberty'' (his phrase for what we today routinely try to capture in the word capitalism). It was built on ''the natural effort of every individual to better his own condition.'' The miracle of the ''invisible hand'' of competition, Smith wrote, was such that the struggle among persons seeking the greatest advantage induced both capital and labor to forever move from less profitable to more profitable employment -- and so regulated economic society like some smooth-running machine.

Smith lived 13 years after his masterpiece was published. But his project to analyze the effects of universal competition soon was taken up by others, notably David Ricardo. It was refined and reduced to a series of ''iron laws'' and dire forecasts of slowing growth and subsistence wages that soon enough earned economics the sobriquet ''the dismal science'' and touched off two centuries of intellectual struggle.

But competition is only part of the story of ''The Wealth of Nations.'' An equally important theme is the contribution of accumulation, investment and the growth of knowledge -- thus, the significance of entrepreneurs, research and development, wars and systems of property rights. In recent years, interest in these mechanisms has begun to regain center stage in technical economics as a new generation of economists has emerged to wrestle with the problem of imperfect competition.

In a recent paper, ''Increasing Returns and New Developments in the Theory of Growth,'' economist Paul Romer of the University of California at Berkeley traced the history of this second, less-well-known proposition. Romer wrote recently of what he called "the incongruity between what economists actually believe and what their models of growth predict. A very large majority of economists believe that private-sector research and development expenditure is an important determinant of long-run potential for growth and that the presence or absence of intellectual property rights is important as well. Discussions of the economics of the firm or industry typically reflect this belief. It is only in formal models of growth for the economy as a whole that these effects have been absent.''

Economics will go on as before, sorting through the consequences of Smith's views. Andrew Skinner, the University of Glasgow professor who has spent the last 20 years on Smith, editing a comprehensive edition of his works and preparing various celebrations, has said: ''Next I'm going to take on Jaimie Steuart. He was the Scottish philosopher who wrote down some of these ideas for the first time, even before Smith.''

In the end, though, Adam Smith may be remembered best as a voice that warned against reformers who seek to do everything at once. ''The man of systems seems to imagine that he can arrange the different members of a great society with as much ease as the hand arranges the different pieces of a chessboard; he does not consider that the pieces of a chessboard have no other principle of motion besides that which the hand impresses on them; but that, in the great chessboard of human society, every single piece has a principle of motion of its own different from that which the legislature might seem to impress on it.'' That doesn't mean that Smith was a government-basher. ''No government is quite perfect,'' he wrote, ''but it is better to submit to some inconveniences than to make attempts against it.''

David Warsh is a columnist for the Boston Globe.