Federal Reserve Chairman Alan Greenspan delivered the commencement address today at hallowed Harvard University, where thousands of America's best and luckiest received parchment keys to the modern economy. At the same time, just across the Charles River and a vast psychic divide, former labor secretary Robert B. Reich gave the commencement address at the Pine Street Inn homeless shelter in Boston, where 75 of America's hard-luck people graduated from rudimentary job training programs.

It would be hard to invent a more vivid display of the nation's two economies: the celebrated prosperity associated with Greenspan's economic stewardship and the little-noticed despair illuminated by liberal party-spoilers like Reich; the Harvard economy with its record numbers of millionaires and the Pine Street economy with its record affordable housing shortages.

At Harvard, swank alumni--including Vice President Gore, Class of '69--crowded into the placid Yard, cheering as officials announced that their five-year fund-raising drive topped the $2 billion mark. At Pine Street, about 250 well-wishers sat beneath a yellow-and-white tent near the Southeast Expressway as Reich sang the praises of a former crack addict with a computer job and a reformed alcoholic turned building manager.

"If accomplishment is measured not by the prestige of the parchment received, but by how far one has come in order to receive it, you deserve the highest of honors," he said.

Greenspan talked about the growth of the information economy, and how it has helped expand labor productivity and improve American living standards. He also acknowledged that behind the good news--more than 20 million new jobs since 1993, the Dow Jones above 10,000, homeownership at an all-time high--lies a persistent gap between rich and poor.

"The . . . expansion of incomes and wealth has been truly impressive, though regrettably the gains have not been as widely spread across households as I would like," he said.

This has been Reich's perennial complaint, that startling drops in crime, welfare and unemployment are distracting attention from the plight of the poor. One in five American children still grow up in poverty; 43 million Americans have no health insurance; more than half a million are homeless on any given night. But for the most part, the poor have been off the political radar screen as the economy soars.

In Reich's brassy memoir of his Clinton administration career, "Locked in the Cabinet," he imagined how an honest dialogue with the Fed chairman might go, with Reich shouting, "Robber baron pimp!" and Greenspan responding "Bolshevik dwarf!" But their messages today were far more nuanced than that.

Reich acknowledges that as businesses have expanded, they have become increasingly willing to hire workers they would normally ignore, creating opportunities for Pine Street graduates. Leslie Killam, 39, had lost her job as a mechanic, her apartment, and custody of her three children when she came to Pine Street, but at the shelter's culinary arts program, she discovered a love for baking. Now she is a full-time employee at a neighborhood bread shop, earning $7 an hour.

"I've got a whole different life," said Killam, who wore a silky green dress and white shoes from the shelter's clothing warehouse to graduation. "I happen to be lucky to fall into something. It's not the best money, but it's something I really like."

The worries of Harvard grads who rented caps and gowns for $23 a pop and spent up to $700 on class rings are on an entirely different scale. Most will end up in careers in business, medicine, academia or law, with starting salaries well over $50,000; most will pursue further education. Among the several hundred organizations that recruited on campus this year, from Goldman Sachs to J.P. Morgan to Microsoft, only six were categorized as "public service" groups.

In a recent online Harvard Crimson poll, three-fourths of the respondents said they approved of the selection of Greenspan as commencement speaker, but one group of seniors walked out of today's ceremony, complaining that his invitation confirmed Harvard's reputation as a pre-professional breeding ground for financiers. Some wore green ribbons today as token pledges to pursue socially and environmentally responsible careers; others pasted orange stickers on their mortarboards declaring "Leaders Not Bankers" and "I-Bank, Therefore I Am?"

"Harvard exists to reproduce the ruling class," groused senior Daniel Morgan, who plans to head to London for a master's degree in cinema and television studies.

But if Morgan and his fellow protesters had lingered for Greenspan's speech, they might have been surprised.

He described himself as an "idealistic central banker," and his advice to the seniors had little to do with finance, and everything to do with decency.

"It is decidedly not true that nice guys finish last," he said. "The true measure of a career is to be able to be content, even proud, that you succeeded through your own endeavors without leaving a trail of casualties in your wake."

To which Reich might well have replied: Easy for you to say. In his speech today, Reich warned that when the Fed raises interest rates as a hedge against inflation, as it is expected to do in the near future, jobs disappear. And the first jobs to disappear do not belong to Harvard graduates; they belong to Pine Street graduates.

"The slightest hint about what the Fed might decide causes Wall Street to buzz," Reich said. "It ought to cause Pine Street to buzz, too."

But Pine Street is still a world away from Wall Street. At Pine Street, a $10-an-hour job is still considered a "great placement."

Still, shelter president Erik Payne Butler--who graduated from Harvard with Gore--believes the Harvard graduates entering "the fellowship of educated men and women" today could learn something from their counterparts from the school of hard knocks.

"There's some humility from realizing life isn't just a stream of never-ending successes," he said. "Life hasn't presented them any big challenges yet. But it will."

CAPTION: At left, keynote speaker Alan Greenspan with Vice President Gore at Harvard. At right, keynote speaker Robert B. Reich and graduate Ken Weathers, right, at homeless shelter.