WASHINGTON — It’s only January, but what may be the year’s most important book on economics has already been published. Called “The Rise and Fall of American Growth: The U.S. Standard of Living Since the Civil War,” it argues that we can’t expect new technologies to rekindle rapid economic growth. Advances in living standards will be modest and grudging. This somber message goes to the heart of the debate about America’s future.

It’s not that the author, economist Robert J. Gordon of Northwestern University, dislikes technology. Just the opposite: He’s fascinated by it, and almost all his 762-page masterpiece describes the huge gains, mostly derived from new technologies, that have transformed daily life since the late 1800s. Until then, writes Gordon, “life and work were risky, dull, tedious, dangerous and often either too hot or too cold.”

We all know what happened. Primitive conditions gave way to modern amenities and technologies. In 1870, there were no homes with electricity, and few — if any — with indoor plumbing or central heating. By 1940, about 40 percent of homes had central heating, 60 percent had flush indoor toilets, 70 percent had running water and 80 percent had electricity.

But in some ways, we succeeded too well, suggests Gordon. The spectacular advances conditioned us to believe that rapid technological progress is an inherent feature of our economic system. Invention and innovation can be dialed up to solve any problem: reversing sluggish economic growth, curing cancer or combating global warming.

Not so, says Gordon. Rapid advances are not assured. What he shows is that technology-driven growth has varied substantially over time. It was fastest between 1870 and 1970 — a period he calls a “special century” — and slower both before and after.

Consider the special century’s crucial technologies: telephones, airplanes, television, synthetic fibers, plastics, assembly lines, chain stores and, most importantly, the internal combustion engine (cars, trucks) and electricity. This last dominated, because it enabled so much more: appliances that reduced housework; elevators that inspired skyscrapers; radio, TV and movies that remade pop culture; machines that overhauled factories; air conditioning that altered economic geography; and computers that manipulated data.

Because “these inventions cannot be repeated,” the rapid economic growth they made possible won’t be repeated either, argues Gordon.

Economic growth essentially reflects two factors: the size and productivity of the labor force. The special century’s impact peaked in the first quarter-century after World War II, when annual productivity gains averaged almost 3 percent. But since 2004, the average has dropped to about 1 percent. If the labor force also grows at 1 percent annually, then overall economic growth is around 2 percent. By historic standards, that’s meager.

Gordon expects more of the same. Moreover, he thinks middle-class income gains will be further eroded by inequality, high debts and an aging population requiring higher taxes to pay benefits.

The superstructure of modern societies rests on an assumed pillar of fast economic growth. People feel that they’re getting ahead and that the collective needs of government can be met without crushing tax increases. If Gordon is right, the future will be more contentious than the past, because the rising incomes that make the process work won’t be rising very rapidly. There will be more emphasis on income redistribution. The competition for scarce funds will intensify, as will (presumably) frustration and disappointment.

Is he right? That won’t be settled conclusively for years or decades, when it’s clear whether new technologies were powerful enough to raise most Americans’ living standards significantly. Gordon’s critics say he has underestimated the power of new technologies, which are not easily predicted. In one respect, Gordon’s focus on private-sector productivity seems misleading. The real productivity problem involves health care and education, largely public services representing a quarter of the economy, where we aren’t getting our money’s worth.

In the debate over America’s future, the issue is not whether to be optimistic or pessimistic. The right approach is to be realistic. The infatuation with technology is a source of strength, but also of simplistic self-deception. What Gordon has provided is not a rejection of technology but a sobering reminder of its limits.

Robert Samuelson is a columnist for The Washington Post.