I am what's now called a "mature worker," a new phrase with a bright future. It's one of those innocent-sounding euphemisms that clutter the language but seem unavoidable in an age when no one -- except TV and radio talking heads -- wants to offend anyone. When "mature" is attached to "worker," it means "older," generally somewhere north of 45. We older workers (I am 56) are becoming a glut on the market and, as a result, are an emerging social problem.

To be precise: In 2000, there were 61 million Americans 45 to 64; by 2010, there will be 79 million, estimates the Bureau of Labor Statistics. The increase is 30 percent, even though the entire over-16 population is projected to grow just 11 percent. Roughly one in three working-age Americans will soon be "mature." We baby boomers are advancing toward old age.

The trouble is that society doesn't quite know what to do with us. For years, the trend has been toward ever earlier retirement. People wanted (it was said) rest and recreation. Companies needed to make room for the young and ambitious (that was us). Retirement emerged as everyone's entitlement -- life's earned vacation. In 1960, 78 percent of men from 60 to 64 were in the labor force, as were 31 percent of those 65 and over. By 2000, those figures were 55 percent and 18 percent, respectively.

Early retirement's lure remains. It's dangerous to generalize about any group as massive as everyone 45 to 65. But some things can be safely said: Most of us have fewer illusions than at, say, 25; we have usually substituted attainable ambitions for unrealistic fantasies. For many, early retirement is still the thing. Plenty of us have huge enthusiasm for work. But others have had enough. They want out.

Some are also being pushed out. Older workers span the spectrum of human potential -- from deadwood to spark plugs. But many are expensive workers. They've received years of cost-of-living and merit wage increases. Their health expenses are rising. When companies want to cut costs -- as they do now -- the temptation to substitute younger (and cheaper) workers for older (and more expensive) workers is powerful. "Early retirement" programs multiply. Experience is expendable.

These pressures for early retirement are understandable. But in an aging society, they're disastrous. Life expectancy is rising. People are healthier. We cannot afford to let more and more able workers go to the sidelines. The social problem of the mature worker is to reconcile society's need (which is to keep more people working longer) with individual and corporate preferences (which favor early retirement).

We need a transformation of work as profound as that which occurred when women flooded the labor market. More older Americans need to move gradually from work to full-time retirement. They need to mix jobs and leisure in ways that seem natural. We need more part-time jobs, we need more jobs with flexible working hours, and we need more jobs that engage people's interests even though promotion prospects have faded.

Little is being done, a new report from the Conference Board, a research group, shows. Companies have a "dearth of strategies to keep mature workers," the report says. The Conference Board did a survey of workers 50 and over. Nearly half (47 percent) said that "more flexible hours" might delay their retirement. A similar number (43 percent) said they would like to work part-time, about two-thirds (68 percent) with their current company.

Some of these problems may ultimately cure themselves. A stronger economy -- and a need for experienced workers -- may impel companies to create new types of jobs. The harder task is to ensure that today's jobs and tomorrow's sustain people's emotional commitment. Older workers often feel overlooked and underappreciated. "All the meaningful assignments," said one respondent to the survey, "[go] to employees who are the same age as, or younger than, the boss -- who is most often in his or her 40s." In the survey, 25 percent of respondents wanted to retire because they no longer felt "respected."

But corporate clumsiness isn't the only problem. We mature workers can also harbor unrealistic expectations. In the survey, about half of workers suggested that a big raise would cause them to postpone retirement. Sure, why not double our salaries! And generational conflicts exist. If too many older baby boomers stay too long in top jobs, they will be resented by those who can't get ahead.

Since the mid-1990s, the share of Americans in their fifties and sixties still working has risen slightly. But we need a bigger shift. Too much early retirement could be bad for us personally and bad for the country. Early retirees may miscalculate. They may spend their savings too quickly -- a danger emphasized by the stock market's decline. A scarcity of workers and a surplus of retirees also invites a wider social injustice. The imbalance may trigger a huge income transfer from the young to the old -- through higher taxes to support federal programs (Social Security, Medicare) and repressed wages to support rising pension costs. This is not a fate aging baby boomers should inflict upon their children.