The Cold War era I grew up in was a world of insulated walls, both geopolitical and economic, so the pace of change was slower — you could work for the same company for 30 years — and because bosses had fewer alternatives, unions had greater leverage. The result was a middle class built on something called a high-wage or a decent-wage medium-skilled job, and the benefits that went with it.

The proliferation of such jobs meant that many people could lead a middle-class lifestyle — with less education and more security — because they didn’t have to compete so directly with either a computer or a machine that could do their jobs faster and better (by far the biggest source of job churn) or against an Indian or Chinese who would do their jobs cheaper. And by a middle-class lifestyle, I don’t mean just scraping by. I mean having status: enough money to buy a house, enjoy some leisure and offer your kids the opportunity to do better than you.

But thanks to the merger of globalization and the I.T. revolution that has unfolded over the last two decades — which is rapidly and radically transforming how knowledge and information are generated, disseminated and collaborated on to create value — “the high-wage, medium-skilled job is over,” says Stefanie Sanford, the chief of global policy and advocacy for the College Board. The only high-wage jobs that will support the kind of middle-class lifestyle of old will be high-skilled ones, requiring a commitment to rigorous education, adaptability and innovation, she added.