THIS SUMMER, for the first time, the number of Americans with jobs edged up over 100 million. Whatever the other troubles of the American economy, it has generated nearly 2 million more jobs over the past year. That's real cause for celeration on this Labor Day. It's an occasion on which to reflect on the strength and resilience of the economy, and of the people who contribute to it. Perhaps it's also a moment to take stock of some of the extraordinary changes that have overtaken this country's labor force over the past generation.

American working people are much better educated than they were in the 1950s--an obvious point, but immensely influential--and they are younger. Many more of them are women. A generation ago, one out of three women worked for wages. Today, it's well over half. But the proportion of adult men in the labor market is down significantly --mainly the consequence of pensions that invite earlier retirement.

As prosperity has risen, the strength of the labor unions has fallen. In the early 1950s, 35 percent of all working people belonged to unions. Currently, the figure is down to 21 percent. You don't have to approve of everything that any union has ever done to find yourself wondering who, over the next generation, will be the spokesman for the inarticulate in the industrial world, and the bargaining representative for those working people whose skill and status cannot ensure them secure niches in large businesses. You may also wonder about the future of political life with the steady erosion of the unions that have been, most of the time in most places, the advocates of enlightened social ideas.

This country is now entering, thanks to the recent tax bill, an era of widening disparities of income. A lot of unions, because of deeper changes, already seem to have entered the era of the give-back. It started well before the air controllers' misguided strike. Many unions are being forced to give back pay raises and contract benefits already won, to preserve employment--and employers. You can think of a dozen recent examples in the most disparate industries: automobiles, airlines, newspapers, groceries. The traditional style of adversary bargaining produced contracts that reached too high, and now the realities--high interest rates, changing markets, sharper worldwide competition--are forcing some of them back down a bit. It's better than watching companies collapse, but it's a bruising process.

The era of the give-backs will, possibly, produce a different style of labor-management relations. A company that pleads for give-backs has to disclose a good deal more about its finances and operations than one that's only debating the size of the pay increase. The give-backs may draw unions more deeply into management, and that's not necessarily a bad thing in a time of highly trained work forces and increasingly blurred lines between labor and management.

The atmosphere this Labor Day is a paradox. The country is enormously prosperous, and Americans enjoy greater personal security than ever. But people seem to be anxious and uncertain about it all. A generation ago, when people had less money and much less security, with the country going through a succession of sharp recessions, there was a durable faith in progress. There are plenty of things to worry about at the moment; this page tries diligently to keep a long list of them fresh in everyone's mind. But it's also worth remembering on this Labor Day that, as people used to say in the Depression, there's bread on the table--put there, this summer, by the wages of the slightly more than 100 million Americans who have jobs.