Utopia is alive and well. And, if advertising copywriters are to be believed, it is right here in Northern Virginia.

To find out about that Utopia, you need only to turn to the current issue of Scientific American magazine. Among its no-nonesense articles is an unprecedented advertising supplement that gushes on for 18 pages about the "advanced technology center" of Fairfax County.

In the "editorial" matter, larded among 13 ads like stuffing in a turkey, the copywriter carries on: "The region has become a home for thousands of questioning minds and the benchmark of technical excellence."

In a sentence that might cause some of those questioning minds to knit their brows, the copywriter says of Fairfax: "From its still rural western edge, one can in equal time and ease visit the museums, galleries, theaters and halls of government in Washington or seek the quieter pursuits of the Appalachian Trail and the Valley of the Shenandoah (sic) in the Blue Ridge Montains. At Great Falls on the Potomac, white-water canoists (sic) can run the rapids while further down . . ." and so on and so, until the writer arrives, still not out of breath or words, at "the nation's most delightful waterland, Chesapeake Bay."

Perhaps he toured the area in a helicopter.

Elsewhere in the issue, editorial matter (the real kind) somberly surveys the sorry state of economic development in less-advanced nations. One author concludes: "All concerned must listen to the voices of the poor, who have paid the highest price for the passing order and can no longer be kept in convenient silence."

No such Cassandra intrudes on the Fairfax advertising supplement. Instead, the prose extolls "the first-class superhighways (that) traverse the area so that virtually no part of the region is more than an hour by road from any other part. Indeed, in few parts of the country can people live and play in such close proximity to their work and with so wide a range of life-style options available."

Take that, Marin County, California!

The high technologists of Fairfax are "competent, bright, and curious people accustomed to working to a high level of technical excellence (and who want) ready opportunities to advance in both their professions and careers."

The Me Decade of the 1970s might have been a little slow in coming to Fairfax, but that apparently means it's spilling over into the 1980s.

What is unusual about the supplement is that the ads are actually less hucksterish than the "editorial" matter that binds the section together. ("In our efforts to find alternate energy sources," reads the Atlantic Research Corp. display, "we have developed a substitute for No. 6 heating oil, using a mixture of coal and water.")

But just as the ads are selling the companies, primarily to attract scientists, engineers and technicians, the "editorial" copy is selling Fairfax County to the bosses of those workers -- the executives who will decide whether Fairfax is the technological Utopia described.

The No. 1 hornblower for the county in recent years has been the Fairfax County Economic Development Authority, which has bought full-page ads in the Wall Street Journal and two-page spreads in Fortune magazine. The ads cleverly capitalize on Fairfax's proximity to Washington. ("The advantages of locating your company amidst the greatest concentration of power and influence in the free world," trumpeted one headline), but in the same breath make this curious and invidious comparison: "When you look at Washington, the view is better from Fairfax County."

Though the authority spends $500,000 a year to tout the advantages of living and working in Fairfax County, executive director David A. Edwards said the agency did not instigate or direct the $150,000 production in Scientific American. The basic idea, he said, began with Scientific American, which wanted a series of supplements (presumably chock-full of advertising) on the advances in high technology in the United States.

Edwards said a firm called Development Counselors Inc. suggested to Scientific American that Fairfax would be a good starting point for the series, and the magazine agreed.

As it happens, Development Counselors is on a $2,500-a-month retainer from the Fairfax economic authority. It is being paid to drum up articles on the county, primarily in technical magazines.

Furthermore, a press release from the authority calls the supplement a "joint editorial and advertising venture by 13 firms in Fairfax County and the county's Economic Development Authority. The firms purchased advertising and the authority provided the editorial copy."

It is true, I suppose, that when you decide to market a product -- whether it's a tube of toothpaste or a county of 585,000 people -- you try to stay upbeat. You don't start wringing your hands and getting problematical.

The technological boom in Fairfax is not a copywriter's fancy; it is actually happening. The county is well positioned to become a leader in computer software advances which may be about to catch up with the innovations in hardware that have been coming out of the Boston area and "silicon valley" in California. Two Fairfax laboratories are conducting critical research on the antiviral drug interferon, which could bring a breakthrough in medical science. Research into alternate energy sources, going on at several other Fairfax companies, could help the United States kick the petroleum habit. All this, and more, can be reported, with honest-to-goodness pride. But do we need Brigadoon, too?

It is jarring to turn to one page of the September Scientific American and see a picture of blind West African villagers -- victims of water contamination -- being led across an arid field, and then abruptly encounter a section that prates on about lifestyles and a county that includes "riverfront estates, condominium townhouses, apartments and single-family homes for every taste and budget . .fs. ."

Maybe the special section should have been sold to Town and Country.