Good lord, The Washingtonian magazine is 20 years old.

You practically have to be a native to remember that first issue, October 1965, with its cover of the Supreme Court building, its 66 black-and-white pages with their leisurely 3 1/2-inch-wide columns and a "Capital Comment" that wanted so very much to be another "Talk of the Town."

Aiming at something it called a "leadership audience," it addressed readers who were desperate to eat, buy, belong to, read and live in what the people in Georgetown were eating, buying, belonging to, reading and living in. Its newest owner calls it elitist.

In the beginning there was a Buchwald piece, of course, and a gourmet tour of Skyline Drive done mostly in captions, and a profile of Sam Gilliam, and a doggedly informative piece on the Watergate, which in those days was just a hotel. Oh, and a survey of new white-collar industries in the suburbs. This was, had we but known it, a portent.

November 1965, a proud announcement: 12,000 subscriptions, 5,000 newsstand sales at 50 cents a copy. On rolled The Washingtonian. Fashion stories. Georgetown's M Street scene discovered. Chinatown. O. Roy Chalk and Capital Transit. Reston. Jeane Dixon. A sidelong reference to Tom Wolfe and "something Clay Felker calls the New Journalism." M Street discovered again.

The New Yorker touch continued to elude "Capital Comment." Washingtonian humor is . . . collegiate. One correspondent insisted she had overheard her child praying, "Our Father, Harold be thy name," a gag that surely dates from the Dead Sea Scrolls or maybe even Joe Miller. But its writers persisted. The Founder & the Heirs

The Washingtonian's leadership has been remarkably stable. Laughlin Phillips, the founder and originally the editor and publisher, soon named Robert J. Myers as publisher, continuing as editor himself, and later, in 1979, sold the property to Philip Merrill, publisher of Baltimore Magazine and five Capital-Gazette newspapers, for $3.6 million. Merrill, with his wife Eleanor as publisher, retained 10-year veteran John A. Limpert as editor, a post he had held five years. Listing Toward Destiny

But there have been changes, all right. Changes in the look, changes in the tirelessly jaunty tone. It began to seem that two sets of editors were at work on The Washingtonian, one group fresh from Consumer Reports, the other apparently from "Ripley's Believe It or Not."

The first gave us lists. Lists! Goodness, we had lists coming out our ears. Jokey lists, scary lists, pompous lists, sly lists, lists to make us feel good about ourselves, lists to make us fear we weren't living in the right neighborhood, hadn't yet seen the right plays, visited the right resorts, been to the right party; lists that challenged us to have our kids at the right school, the right tennis camp, the right orthodontist; lists to inspire, to amuse, to irritate, to outrage, and, everlastingly, inescapably, alphabetically, restaurants, restaurants, restaurants.

Now, lists are in fact a form of conceptual art. The trouble was, The Washingtonian took them literally and actually dug up, for example: the 101 worst problems of the Potomac; 9 government poets; the 12 best campsites; 5 best bartenders; 5 most useless government agencies; 6 delicious cooking schools; 12 ways to improve your back yard; 17 sexiest men; 10 sexiest women; 10 most common cosmetic surgery operations; 59 places to listen to music; 12 supercreative people; 99 nice things to do this summer; 26 parks in the area; 40 people who have pizazz; 23 women with growing political clout and, a piece that lives in memory, the 8 most important Vietcong.Guidance Counseling-----

And guides! We got guides in almost all the 240 issues: guides to area day camps; to golf courses; to character saloons; to Christmas gifts; to ski areas; to indoor tennis courts; to marinas; to the best junkyards; insiders' guide to New York ("Most New Yorkers walk the shorter distances. It's the way to see the city and . . ."); car owners' survival guide; summer survival guide; Christmas survival guide; bus riders' survival guide; teen-age survival guide; insiders' guide to downtown D.C.; and a synopsis of the 20th century in 90 seconds.

Over the years, inflation pumped up the numbers from, for example, six seafood restaurants to 50 very best restaurants to 71 restaurants rated to 444 good restaurants to 499 good restaurants. Restaurant ads boomed too as the magazine's page count mushroomed to 300 and beyond (with the anniversary issue a record 400 pages), the price to $1.95, the circulation to 135,000.

Possibly the silliest guide is the annual Map of the Stars, a fixture in the magazine for seven years now. It began with the notion that Washington was becoming the Hollywood of the East and pictured the homes of the powerful, from Burger, Barry and Kennedy to Harriman, Hechinger and Nader -- with street addresses.

By 1981, in the wake of a complaint by Art Buchwald that a Washingtonian reader had burglarized his house, the magazine stopped printing the addresses and settled for just the neighborhood. The feature nevertheless continues to immortalize local celebrities along with people we never heard of, and sometimes to get the wrong house entirely. In the magazine's latest reprise of the feature, at least three homes did not house the people who were said to inhabit them.

The grand culmination of this obsession with lists (didn't F. Scott Fitzgerald fear he was losing his mind because he couldn't stop writing them?) is the annual Best and Worst extravaganza, the road show of Esquire's "dubious achievements awards": a typographical quilting bee that covers page after page with a phantasmagoric fly's-eye pattern of tiny pictures and boxes as it rates vanilla ice creams, cannoli, strippers, potholes, face lifts, congressmen and so on. Fear, Sex & Georgetown

In the midst of this fascinating world of numbers, Washingtonian's other set of editors confronted the readers with a relentless series of scandals, disasters, heavy-hoofed satires, apoplectic fist-shakings and great gongings of doom.

"Scandal of the Potomac!" bellows one headline. "Washington's Worst Drug Problem!" "The Climate of Fear in Washington," "Burglary Ring in Georgetown," "What's Wrong With Our Doctors," "The Worst Problem in DC," "The Latest Airport Outrage," "Sex and the Singles Bars," "National Airport -- The Great Filthy Beast of the Potomac," "How Safe Are You?" "Why Can't I Fall in Love?" "Fear of Terrorism" . . . and this shocker: "Washington Has No Performing Arts Critics!"

Beneath these screamers one could sometimes find articles by a long roster of writers-about-town, plus a handful of nationally known political reporters. It turns out the scandal of the Potomac is that it's dirty. The great drug menace is alcohol. D.C.'s worst problem is housing. Interesting stories, useful stories, they nevertheless leave the reader wondering what it was that so electrified the headline writer.

This year The Washingtonian won two National Magazine Awards for articles on the military hierarchy and area medical care. And, reflecting owner Merrill's ongoing campaign to make the contents "more consequential," virtually every issue contains at least one major piece on concerns of the day.

On a tour of the offices on L Street, editor Limpert said an article idea emerges from conferences to be matched up with a writer. An ex-newspaperman (San Jose Mercury-News, UPI), Limpert, 51, speaks with satisfaction about his magazine, its formula and what it attempts to do.

The profiles have indeed now and then brought to our attention people years before they moved to center stage. Thus, we met Melvin Laird as a Wisconsin congressman, Rose Mary Woods as Nixon's "palace guardian" in 1969, the rising young Marion Barry, Robert Short, John Hechinger, the still-healthy Julius Hobson and Vince Lombardi and the unreconstructed Wilbur Mills; Anna Chennault, the young Carter Brown, George Allen, Clark Clifford, Jeane Dixon (again), the patient Art Buchwald (again and again), Ethel Kennedy and most recently -- and irreverently -- "Megatrends" author John Naisbitt. SO the D.C. Elite

Though he won't comment on the reputedly remarkable profits, Merrill readily quotes other figures: 11 percent coverage of the Washington market area with an unusual 5-for-1 pass-along rate; the highest market penetration of any city magazine except LA magazine; an average subscriber with $84,000 in household income and a net worth of $300,000.

"Ninety-six percent of our subscribers went to college, 55 percent went to graduate school -- how about that? -- and 2 percent have run for public office," he added. "The purpose of the magazine is to appeal to these people, the upper 10 percent. We try to explain how to get the best out of life in Washington and to illuminate the institutional forces at work here: how to cope with the system. Our third function is as an arbiter of taste and judgment in a way a newspaper can't really be. You want to go to dinner? We can give you the five best steakhouses. The best exhibits at the National Gallery. Ten good movies . . . Service pieces . . .

"We're on the same wavelength as our readers. We're unabashedly elitist."

Speaking of bashing, the magazine has shown a special fascination with The Washington Post. Hardly a month has gone by without some revelation of arcane in-house scuttlebutt, bulletin-board memos or personal failings among the more familiar Post names. In its day The Washington Star was a regular target, too. But then, everybody everywhere loves to hate the local paper. It's called transference.

One of Washingtonian's surprises has been the success of its personals section, which since 1976 has ballooned from eight items to 22 columns of people "In Search of" one another. Screened by a staff lawyer, they have managed to avoid the unbuttoned look of, say, The Village Voice personals. Full of "tall, attractive" nonsmokers, caring sharers and brand-name references ("prefers Vibram soles to heels, Britches to Garfinckel's, Levis to Calvins . . ."), they offer piquant insights into the mind of the yuppie.

"At first we had two little old ladies taking the ads," Merrill said. "Now it's all computerized. They're all ages, not just kids. There's a lot of lonesome people out there."

A few years ago one ad gave the lawyer conniptions. Somebody was looking for a "WCBM lover," and the whole staff was baffled. What sort of kinky deviation was this? People were doodling initials all over their desks. B/D, S/M . . . nothing seemed to fit.

The lawyer was adamant. No translation, no ad.

Finally the mysterious initials were shown to someone who was thinking of other things.

"Oh, that," she murmured casually. "It's a radio station."