WASHINGTON — Art Liscano knows he’s an endangered species in the job market: He’s a meter reader in Fresno, Calif. For 26 years, he’s driven from house to house, checking how much electricity Pacific Gas & Electric customers have used.

But PG&E doesn’t need many people like Liscano making rounds anymore. Every day, the utility replaces 1,200 old-fashioned meters with digital versions that can collect information without human help, generate more accurate power bills, even send an alert if the power goes out.

“I can see why technology is taking over,” says Liscano, 66, who earns $67,000 a year. “We can see the writing on the wall.” His department employed 50 full-time meter readers just six years ago. Now, it has six.

From giant corporations to university libraries to start-up businesses, employers are using rapidly improving technology to do tasks that humans used to do. That means millions of workers are caught in a competition they can’t win against machines that keep getting more powerful, cheaper and easier to use.

In the United States, half of the 7.5 million jobs lost during the Great Recession paid middle-class wages, and the numbers are even more grim in the 17 European countries that use the euro as their currency. A total of 7.6 million midpay jobs disappeared in those countries from January 2008 through last June.

Those jobs are being replaced in many cases by machines and software that can do the same work better and cheaper. “Everything that humans can do a machine can do,” says Moshe Vardi, a computer scientist at Rice University in Houston. “Things are happening that look like science fiction.”

Google and Toyota are rolling out cars that can drive themselves. The Pentagon deploys robots to find roadside explosives in Afghanistan and wages war from the air with drone aircraft.

The advance of technology is producing wondrous products and services that once were unthinkable. But it’s also taking a toll on people because they so easily can be replaced.

In the U.S., more than 1.1 million secretaries vanished from the job market between 2000 and 2010, their job security shattered by software that lets bosses field calls themselves and arrange their own meetings and trips. Over the same period, the number of telephone operators plunged by 64 percent, word processors and typists by 63 percent, travel agents by 46 percent and bookkeepers by 26 percent, according to the U.S. Labor statistics.