Victoria Romero has taken home paychecks from plenty of employers over the past decade.

Jobs at Wendy's, in a Giant Food mail room and at an art supplies store in Montgomery County that went belly up all paid near the minimum wage. The jobs served as stopovers as Romero swung back between work and welfare.

"Not enough money to take care of a tick," said Romero matter-of-factly.

But the check Romero received about 18 months ago was different. Imprinted with the Statue of Liberty, it was the first of many such checks she has brought home from a job as a receptionist at the National Cancer Institute in Bethesda, work that pays more than $100 a week above what she's ever earned before. More importantly, in her mind, it represents hope for a different future, one in which she has a career--not just a job.

"It feels so good to have a job, to be able to take care of yourself and take care of a loved one," said Romero, 34, who has a 17-year-old son. "It's just a good feeling."

Romero is a singular image on a broader landscape, one individual whose life has been changed by the most durable economic expansion in history. For the first time in many a decade, the promise of "a rising tide lifts all boats" is beginning to ring true with some of those at the bottom of the economic ladder. And while no one can predict when the current boom will end, some experts say there are trends at work in the economy that could make the current employment gains among the bottom rung long-lasting.

That would be a welcome development. Even with the recent gains, the poorest fifth of the population is getting 9 percent less after-tax income than it did in 1977, and real economic gains still elude some of the country's most impoverished areas such as Appalachia and the inner cities. Many experts worry that the technology-driven economy is becoming bifurcated, with huge wealth available to Internet-savvy workers but precious little for those who lack even a high school diploma.

Still, others say the environment has improved markedly from just a few years ago.

"I think we're seeing prosperity that is more broadly shared," said Labor Secretary Alexis M. Herman. "There's some indication people are getting better-quality jobs."

Herman said employment gains for workers historically left out in boom times benefit all of society, helping keep people away from lives of crime and encouraging greater consumer spending that keeps the economy humming along.

"I always say the best crime prevention strategy is a job," Herman said.

The monthly unemployment rate for all workers has hovered around 4.2 percent and 4.3 percent since March; it was 4.2 percent in August. While that is an impressive gain from the 7.3 percent rate in January 1993, when President Clinton took office, it pales beside the drop in unemployment among blacks during the same period--from 14.1 percent to 7.8 percent. Among black teenagers, a group that has always suffered high unemployment rates, the decline has also been dramatic. Black teen unemployment was 40.5 percent in January 1993. Last month, it was 28.6 percent.

People of Hispanic origin have also seen considerable improvement. Their rate of unemployment has fallen from 11.3 percent in 1993 to 6.5 percent today.

That's been a benefit to Amilcar Aleman, an El Salvadoran immigrant who fled his native country during its war in the 1980s, settling first in California. The son of farmers spoke little English and his shyness limited his ability to pick up the new language.

When he moved to Rockville in 1990, as a 15-year-old boy, Aleman chose not to go to school and instead took a series of low-paying jobs. He cleaned the theaters at Wheaton Mall and bused tables at local restaurants.

In 1995, he got a break at the Silver Diner. Aleman was working as a cook at both the Silver Diner in Rockville and at a nearby seafood restaurant. To retain its hard-working employee, the diner agreed to match his combined wages at both restaurants. Then, the chain began promoting him. Now, he works as the kitchen manager at the Falls Church diner, earning about $45,000 a year in salary and bonuses. And today, his employer is prepping the 24-year-old Aleman for a store manager position, having paid for his English-language classes, and is helping him obtain permanent U.S. residence.

"Companies have now focused much more dramatically on identifying jewels in the rough and investing in those guys and their leadership, language skills, people skills and education," said Patrick Meskell, senior vice president of human resources for Rockville-based Silver Diner Inc.

"Not everyone comes to you with the skills you want," Meskell said. "If they have the right personality, you can teach them the rest. That has been a lesson for us and other companies: Stop looking for perfection. You cannot train attitude."

Aleman says his life has improved dramatically along with his work history. He once took buses or relied on friends for rides; now he leases his own Honda Civic. He had shared a two-bedroom apartment with six people; now he lives in a rented house with his sister and brother.

But he remains cautious about spending too much money despite the progress he's made in the vibrant economy.

"I am still afraid," Aleman said. "I have a job today. How about tomorrow? You never know what will happen."

As Aleman's experience shows, the long expansion has yielded not only declines in joblessness, but equally impressive gains in income. In the past three years, wages have risen 5.6 percent for all workers after adjusting for inflation. Those in the bottom 25 percent of the income distribution, though, have seen wage gains of 7.5 percent in the same period while those at the very bottom, the lowest 10 percent, have seen their income jump by 9.1 percent. Blacks and Hispanics, likewise, have enjoyed even stronger percentage gains in income.

Economists say the gains occurring among the lower ranks of the labor force are the result of several factors, including changing demographics, governmental policies such as tax credits for lower-paid workers and welfare-to-work programs, as well as overall changes in societal attitudes toward drugs and crime. But the single most important reason for the improvement at the bottom is the continued economic expansion, which has sucked up into the work force just about every available worker with even the barest of skills. One additional explanation: a huge explosion in the prison population during the 1990s, which has removed some potential workers from the labor force.

But underlying all of these forces is the powerful effect of changing demographics. From 1960 to 1978, the percentage of workers in the labor force under 25 ballooned, reflecting the so-called baby boom, but that wave is now ebbing. In a forthcoming article in the Brookings Review, Harvard economist Lawrence Katz contends that unemployment rose by slightly more than two-thirds of 1 percent from 1960 to 1979 because of changes in the age structure of the work force, then dipped by a roughly similar amount from 1979 to 1998.

The aging of the baby boomers and the impending retirement of many of them could lead to continued tightness in the labor markets, many economists argue, reinforcing some of the gains in employment and income that are now being felt throughout the economy.

This continued strong demand for employees--about 19 million new jobs have been created since the beginning of the Clinton administration--has led many companies to hire and train people with less education and fewer work skills than in the past. That has pushed up incomes among workers in the bottom fifth of the income ladder at rates not seen in decades.

"The people getting in now are in the service sector," said Greg Irish, director of the D.C. Department of Employment Services. "They're changing beds, working in fast food places. Those industries have a shortage of labor so they're willing to take them."

But Irish said he is less certain of whether these workers will remain employed if and when an economic downturn arrives.

"What happens when it slows down?" Irish asked. "Some of these people will be immediately laid off because they don't have the skills. We have people coming to us for jobs who are not skilled, who can barely read and write."

While the changing demographics and other factors have converged to improve the employment picture during Clinton's tenure in the White House, liberal critics have said his administration could have done even more in these best of times by focusing directly on helping those in poverty.

Indeed, the picture is still brightest for the better-educated--and for white men and women, compared with blacks and people of Hispanic origin. But this economic expansion is reaching deeper into society than that of the 1980s, which largely benefited the most well-off segments.

"The tight labor market helps those folks that are most employable, college-educated and skilled workers," said Mark Vitner, economist with First Union Capital Markets in Charlotte. "But it really opens up a whole world of opportunities. Companies are taking a chance on people and training them."

While the last hired may be the first fired, as is usually the case during economic downturns, Vitner and other economists said the plethora of training programs now being used by employers means some of these new entrants to the workplace will be better positioned to weather any economic storm.

"Once you get someone into the work force, they become somewhat skilled," he said.

It's this upward mobility that may be the lasting hallmark of the 1990s economic boom. Huge demand for high-tech workers and people with advanced college degrees has drawn workers up through the ranks. As companies poach one another's best workers and lure the best and the brightest with fat salaries, stock options and other benefits, they create new openings for workers further down the ladder. Eventually, even those with minimal skills and work histories find themselves in demand.

That's what happened to Gregory Scarborough, 44, of Temple Hills.

Scarborough had worked as a security guard and before that, as a supervisor of landscaping crews. "Security work was okay, but I wanted to get outside of that," he said.

One of his security assignments last year took him to a telecommunications installation site in Rosslyn, where chats with technicians brought back memories of one of his father's favorite hobbies, tinkering in the basement with television and radio sets.

Scarborough began wondering how he could get a similar job. At the suggestion of a technician, he enrolled in a training program for starting telecommunications technicians run by Capital Commitment, a private, D.C. job training program supported by the region's leading telecommunications firms.

Soon after graduation from the six-month course, which cost him $575, Scarborough landed a job with a new information technology company in Bowie, L.B. Price Communications. Scarborough now works alongside technicians from Bell Atlantic Corp. and other major telecommunications companies on central telephone company switching networks.

Scarborough declined to say what he now makes, but starting salaries in the technology field are certainly higher than those for security guards and landscapers. What's more, Scarborough now believes he has grabbed a rung on the career ladder for the first time in his working life.

In some cases, employers have no choice but to take workers with fewer skills than they would like--or have historically demanded of applicants. The pool of available labor is just too tight.

Such is the case around Detroit, according to Steve Armstrong, who runs the local office of temporary services company Kelly Services Inc. Armstrong supplies workers on a contract basis to fill vacancies in customer service, manufacturing and retail.

"Several years ago, the available work force had more skills than today," Armstrong said. "These people, if you are talking about people who are breaking a chronic chain of unemployment, they have a desire to work but lack a lot of hard skills."

Armstrong said that puts additional burdens on companies and services such as his to work more with job applicants and potential employees. At Kelly, for instance, Armstrong uses an interactive CD-ROM that helps customer-service call-center workers learn basic communications skills.

How all of these new and now upwardly mobile workers will fare when the economy inevitably slows remains to be seen. In private, some employers say a recession would allow them to replace their least desirable employees--the rude salesperson, the employee who shows up late and the cashier who gabs on the phone.

But such comments are the exception. In an economy that has produced low unemployment and low inflation, the main concern among employers nowadays is how to find workers, not how to lay them off.

And that's good news for people like Victoria Romero, who, more than any statistic, can capture the essence of the improved economic life for lower-tier workers.

"I didn't want to be 30, 40 years old asking people if they wanted fries with their shake," she said. "I knew there was something more for me."