If we learned nothing else during the 1970s and 1980s, it is that, in a certain broad and deep fashion, economics works. If the price of oil goes up, then people demand less oil, the supply increases as producers come forward eager to sell what they've got, and the price of oil comes down again -- all because individuals, left to their own devices, tend to choose what is best for themselves. There were lots of fine points to be learned along the way, but the experience of the Organization of Petroleum Exporting Countries had the force of a giant experiment.

The reassertion of economics to its rightful place in our understanding of how the world works may come at the expense of sociology, which in Europe and America at least, has flourished during the past 150 years as something of an alternative to economics. If you didn't like big business and the direction things were taking in the modern world, you could always turn for solace to the heirs of Karl Marx, Emile Durkheim and Max Weber.

There you would find critical stances, ranging from mild to militant, whose shared principal concern was for the ways in which social environment affects the individual: alienation, anomie, the psychology of the mob and all that. There was not much attention to the other way around, the effect of individual decisions on the social order, not even in Weberian studies of bureaucracy, but never mind. Generations of some of the smartest people around had built an elaborate gym in which to pump intellectual iron, and afterward you could use your degree for something else.

In the last 20 years, however, sociology -- all of sociology -- has begun to wear a little thin. For one thing, it ran into evermore blind alleys. The great abstract ziggurat of structural-functionalism, erected largely by Talcott Parsons and his colleagues at Harvard, is the prime exhibit here: It offered plenty of systems and subsystems, but rarely a glimpse of real life.

For another, the collapse of the governments of Eastern Europe has left a segment of the field discredited, exposing it for the meretricious mumbo-jumbo that it is.

One always interesting thinker who has been working overtime to end -- or at least diminish -- the ongoing battle between economics and sociology is James S. Coleman, the University of Chicago sociologist. The publication this fall of his "Foundations of Social Theory" (Harvard University Press) is probably the most important thing to happen in sociology in 50 years.

Coleman is no shrinking violet in the cause of sociological analysis. His report on the effect of segregation in education was used by many -- including him, for a while -- as a brief for busing. A later study demonstrated conclusively that the white flight to the suburbs was a direct result of busing, and that parochial schools did a better job than public ones. After reviewing the data, Coleman came out for a system of educational vouchers. For the last 10 years or so, Coleman has teamed with economist Gary Becker at a Chicago workshop that has been the mecca of all those seeking to go beyond the disciplines of sociology and economics toward a broader truth.

Now he is determined to sum it all up with a grand theory, in the tradition of Marx, Weber and Durkheim. The title self-consciously echoes the title with which a young Paul Samuelson transformed economics in 1947. Whether Coleman ultimately succeeds, he's certain to set the agenda for many years to come.

The hinge on which the book turns is the theory of "rational choice." Sociology has always been good at examining the influence of the social setting on the individual, Coleman says, but it's been downright poor at moving the other way. This "micro-to-macro" problem can be solved simply by assuming that people in general act in a purposeful way -- not, perhaps, quite as simply as the "utility-maximizers" of economic fame, but in a generally coherent and meaningful fashion. People who buy and sell oil are rational choosers; so are parents who send their children to school. This simple assumption provides the bridge to economics.

But it's not just individuals who act, Coleman says, especially in the modern world. Institutions play an increasingly important role, and any good theory of society will have a major place for corporate actors. Contemporary societies are not cumulative and accreted -- they are "constructed." Contemporary societies "are more like modern cities of skyscrapers and tenements than like the honeycomb of dwellings on the island of Mykonos or the cumulated complexity of a coral reef."

"Just as the constructed physical environment ... requires its architects, constructed social organization requires its architects. These will be the social scientists of the 21st century," Coleman writes. And their tasks will be not merely to build and supervise markets, but to repair the cities, reinvigorate the schools and restore viability to the fundamental institution of the family.

Coleman's book represents the intellectual journey of an immensely clever and powerful mind. And this time he's probably right in his assessments -- of sociology, of economics and of the future.

David Warsh is a columnist for the Boston Globe.