The history of any Big Idea, regardless of field or discipline, is invariably rooted in the thrill of epiphany. Archimedes had his bathtub. Newton had the pendant bough of an apple tree. Paul Krugman, somewhat less famously, had the departure lounge at Boston's Logan Airport.
Long before he became a celebrated columnist for The New York Times, inspiring both adoration and outrage for his withering, relentless critiques of the Bush administration, Mr. Krugman was a frustrated young economist struggling for recognition.
Yale University had decided not to give him a research fellowship. Colleagues weren't showing much interest in his theory of trade - nor, for that matter, were influential economic journals.
But in 1979, as he waited to catch a flight to Minnesota, he had what he once described in a brief autobiographical sketch as a "revelation."
"Another patch of fog lifted," he recounted, "and I saw my way clear to integrate monopolistic competition and comparative advantage."
Okay, as Eureka moments go, this one isn't likely to supplant the discovery of gravity. But it was enough to revolutionize the study of global trade patterns and vault him into the firmament of respected academics, a place that was cemented this week when - in a surprise to many, himself included - he was awarded the Nobel Memorial Prize in Economic Sciences.
Not that he doesn't have the credentials. But some observers felt the Royal Swedish Academy of Sciences would take pains to avoid the spectre of a politicized award on the eve of the U.S. election: Mr. Krugman has not merely launched acid attacks against President George Bush (whom he accused last year of leading the country into "strategic disaster and moral squalor"); he has increasingly done so to Republican candidate John McCain, whom he recently described as "more frightening now than he was a few weeks ago." Mr. Krugman, 55, was defensive on this point with reporters.
"Nobel prizes are given to intellectuals," he said after receiving the award. "A lot of intellectuals are anti-Bush." The Academy, meanwhile, insisted that it made its selection solely on the basis of his economic research, particularly in two key areas: his new trade theory, and his later work on economic geography.
In the former, he countered centuries of received wisdom surrounding trade patterns: that countries are different, and will trade with one another based on what their comparative strengths are. England will export wool to Portugal, for instance, while Portugal will export wine to England.
But that model failed to account for why a handful of countries dominated trade, and did so in many of the same areas, with little obvious advantage. For instance, Sweden will import BMWs from Germany, and the Germans will import Volvos.
Mr. Krugman recognized that consumer demand for diversity of choice was also a fundamental driver of trade flows, allowing similar countries to exchange many of the same goods.
Likewise, his work on economic geography showed how transportation costs, coupled with greater economies of scale, lead to higher wages, in turn increasing migration into major cities.
If both of these ideas sound simple, it is because they are - deceptively so. Colleagues and fellow academics hold this out as one of Mr. Krugman's strengths, and is undoubtedly a hallmark of his success as a columnist, as well: an uncanny ability to create lean, crisp models to illuminate complex ideas.
"When he was doing new research, he had almost a unique skill at creating very, very simple theoretical models," says longtime colleague Avinash Dixit, a professor of economics at Princeton, where Mr. Krugman still teaches a few classes.
"It was like wielding a stiletto that went right to the heart of the problem."
Inspired by science fiction
Mr. Krugman was born in Long Island, N.Y., in 1953. His father worked for an insurance company and his mother was a housewife. As a kid, he was consumed with science fiction - particularly Isaac Asimov - and credits this childhood passion with propelling him into economics. In his Foundation Trilogy, Mr. Asimov devised a group of characters known as "psychohistorians," who save civilization. This group of social scientists had no corollary in the real world, but the young Mr. Krugman decided that economics was the next closest thing.
"The power of economic models to show how plausible assumptions yield surprising conclusions, to distill clear insights from seemingly murky issues, has no counterpart yet in political science or sociology," he once wrote.
Mr. Krugman showed promise from a young age, according to Jagdish Bhagwati, a Columbia University professor who taught him at the Massachusetts Institute of Technology during the late 1970s. "I gave him some work one summer and, in three weeks, he came back with a finished paper."