Behind today's record-high unemployment for the postwar period lie permanent shifts in how and where we work. Prosperity will not soon return to all sectors of the economy, even when average business profits start to gain. Among the major employment trends:

* The decline of the skilled blue-collar worker. Production workers, predominantly male, are the hardest hit in any recession. Fewer people buy goods, so less goods have to be produced. Over the years, blue-collar workers have adapted their lives to cyclical layoffs, through private savings and union-negotiated programs for supplemental unemployment benefits. Their typical unemployment strategy: Wait it out.

But this recession has made it clear that thousands of blue-collar jobs are vanishing forever. To become competitive with the Japanese, for example, American automakers will have to turn out cars with half the present number of workers, according to William J. Abernathy of the Harvard Business School. The steel industry is shrinking. The probability of continued high mortgage rates puts a damper on housing and the home-appliance industry.

Thousands of blue-collar workers will have to train themselves for other work. Many will never again earn as high a real wage as they earned in the 1970s. High-school graduates should think about computer-service, telephone-repair and office-machine maintenance jobs, instead of leaving their resumes at the local industrial plant.

* A surge in women's work. Many more women work in low-paid service industries, like restaurants and hospitals, than in production industries. During this recession, layoffs in the service sector have been far less severe. For example, the unemployment rate among communications and telephone workers was only 2.2 percent in the second quarter, compared with 22.1 percent in the steel industry.

Throughout this recession, adult female unemployment has been no worse than adult male unemployment and sometimes a lot better--an unprecedented sign of job stability. Usually, female unemployment is much higher.

As the economy recovers, low-level female workers will find work more readily than their male, blue-collar counterparts. They'll be nurse's aides, clerks, child-care workers, sales personnel and fast-food workers. But despite the demand for their services, they'll still be paid the lowest possible wage. The way to prosperity for women continues to lead away from women's work and into men's jobs.

* The intractability of teen-age unemployment. Jobs for young people steadily eroded over the 1970s, for several reasons: Many farm jobs vanished; federal minimum-wage laws may have priced young people out of the market in low-wage areas of the country; also the giant baby-boom generation entered the work force and displaced the least-skilled workers, many of them young.

The usual teen-age unemployment strategy: Work part-time and "off the books." Parents may have to support their children longer than they expected. Working-age teen-agers make up about 9 percent of the population but 20 percent of the unemployed in June. White teen-age unemployment stood at 19.4 percent; black, at a shameful record of 52.6 percent.

* An improvement in the family support system. About 70 percent of the unemployed live in a family where someone else is working, according to a recent study by the Labor Department. Two-income families manage joblessness much better than others. The annual median income of a working couple drops 31 percent if the husband goes through a period of unemployment, and 23.5 percent if the wife is laid off. By contrast, the income of a single-parent family drops 41.3 percent if the parent is male, and 43 percent when the single parent is female.

* The growing armies of the unemployed, stranded in the Sun Belt. Technical, professional and secretarial jobs can still be had in the nation's few remaining boom towns. But skilled factory work is scarce, and unskilled work is almost nonexistent. Authorities in California, Colorado and Texas report people sleeping in cars and knocking on church doors for food.

When work is found, it often pays much less than the migrant expected. Employment specialists advise the unemployed to leave their families at home when they venture out for work. Make a final family move only when you have a job and a place to stay.

* The growth of white-collar America. More than half the work force now wears a white collar to work. For the younger generation, education, technical training and social skills will be the pathway to success