Downtown, Duke Street is skinny. It skitters through Old Town Alexandria, two lanes wide, up a rise to the Masonic Memorial, then back down to the Shirley-Duke shopping center.

It ducks and darts past a few 7-Elevens and fast fooderies. Then, for no apparent reason, it becomes four lanes, divided. And there on the horizon is Condo Canyon.

Condo Canyon is the three square mile flanking Duke Street, just east of Interstate 95. There sit about 20 major apartment complexes. They are home to about 12,000 people.

The condos of the canyon are all things to all those people, or at least they style themselves that way.

The area is relentlessly promoted as The Place for total-environment living - the one part of the Washington area where shops, soirees, schools and splendor are both close-by and common.

Just ten years ago, the area was woods. Today, the overriding visual impression is of concrete - towering high-rise buildings, sidewalks, roads and plazas. The overriding noise is auto traffic. The overwhelming "feel" is suburban comfort. No slums. More Lincolns than Volkswagens. Curbs new enough that the surveyor's markings still show.

The style is very Florida in the sense that most buyers have chosen Condo Canyon to get away from someplace else. But the Canyon is also very California in its amusements and conveniences. Swimming pools, saunas and underground parking are averywhere, and now there is even a condo that will rent you a place gardenias.

But make no mistake: This is Washington. Security precautions are elaborate. Many neigbors remain strangers. People live here largely because it is near where they work - and near a superhigh way that will get them there.

Their buildings nestle into the southwest corner of Alexandria, and in addition to the developers of the area, it is the city that has gotten rich from the Canyon real estate explosion.

In 1967, the land in census tracts 3.03 and 4.00 was valued by the city for tax purposes at about $18,000 an acre. It is now valued at about $2 million an acre. The 37-acre Watergate at Landmark complex, not yet finished, is nevertheless already valued at $56,119,800.

The big boom begin in 1973, in part because a sewer moratorium was imposed that same year in neighboring Fairfax County. At the same time. the city changed Condo Canyon's zoning from industrial to residential-commercial.

In 1973 and 1974 alone, 2,002 housing units were constructed. The 1970 census total for the area was 5,686. The city planning department estimated 1975 total at 11,643. The projected 1980 total is 18,000.

The selling of Condo Canyon has produced new and wondrous mutations of the English language - not to mention mutations of the truth.

"Come lose yourself in a maze of exquisite gardens," trumpets one ad, for a condo where no gardens yet exist.

Amenities "are on a rational, elegant scale," declares an ad for another condo, without explaining how any place can be both at the same time.

"Stroll around this 37-acre wonderland any time," suggests a Watergate ad, which does not mention that most of the acreage is either covered with concrete or in the process of being bulldozed.

But the pitch is working on somebody. New residents can be seen moving in daily. They are families and singles, lovers and rommates, and most seem happy.

They weren't always flocking to buy. Sales were slow at many condominiums for most of 1976 but in recent months, they have picked up considerably.

Nor is life one smooth ride after moving in. Tenants must pay for city trash collection, even though they also pay for it as part of condominium fees. There are also rumblings of poor city police response time. This month, condo owners in several buildings began to form an association to protect their interests.

But most buyers have chosen Condo Canyon for its convenience and resale potential, and convenience is the key for renters, too. Still, the styles of the buildings are far from identical. There are partying buildings, exclusive buildings, transient buildings and leave-me-alone buildings. Rents range from $180 to $500 and above, sales prices from the high 30s to the mid-140s. In other words, something for everybody.

The following is a look at some of those "everybodies:"

PLACE ONE: 5500 Holmes Run Pkwy. 300 units. Approximately six acres. Construction cost uncertain, but believed to be about $12 million. Owned by the McCarthy Corp.

Place One - there's a sort of snap-your-fingers ring to it. It might be a disco. Or a restaurant owned by a football player. Instead, it is one of the newest arrivals in Condo Canyon.

Its tone, like its title, is definitely upbeat. Posh lobby. Jazzy muzak playing softly in paneled elevators. A fountain out front. Fifteen stories of Valhalla-by-the-Freeway, overlooking the babbling Holmes Run.

Where else, would a young woman named Golden McPeak live?

But McPeak didn't choose Place One because of its trendiness. Her roommate's parents simply offered a good deal on the rent for a two bedroom apartment they own there. Despite misgivings about high-rises, McPeak was won over by the way the morning light came through the 14th-floor windows.

Place One is, according to McPeak, far from the singles' roost its name might suggest.

"It's got a good cross-section of people - retirees right down to young singles," she said.

McPeak, a 26-year-old State Department secretary who came to Washington 4 1/2 years ago, is a person who could probably live anywhere and like it.

"I'm such a lucky person. I love my job, get along well with Kathy, my roommate," she says."I guess how to be happy single.

"I came from a town in the Missouri Ozarks - El Dorado Springs, it's called. It has about 3,000 people in it. When I was 18, I took the civil service exam."

Her score landed her a job at Wright-Patterson Air Force Base in Ohio. There, she did a couple of years toward a bachelor's degree at night. Then she came here. She plans to stay "indefinitely."

"I like the pace. In some ways, it's not too different from small town life. But I could never go back there."

Nevertheless, McPeak has sought out many things here that she enjoyed there,. And some revolve around Place One.

For example, "I was a Girl Scout, and I loved it." So when she came here, she volunteered to help out a Lincolnia Girl Scout troop, only to find herself the leader for two years.

When she moved into Place One in October, she volunteered to help get the social club rolling. Now she is in charge of a rsurvey to determine what residents want in the way of recreation.

"I've spent hours on this thing," she said, as she heaved a cardboard box full of completed forms up on the sofa. "So far, it looks like the theater-going group is the most popular. And we're going to offer a rock-climbing course, even though only five signed up. I think that's enough, don't you?"

McPeak said she has not had trouble finding enough to do socially at Place One. No lonely evenings in front of the tube for her. As a veteran Washingtonian now, however, she admits she has "learned through the years to be more cautious.

"Oh, yes, my mother still worries about me," she said. "But the longer I'm here, the better she feels."

WATERGATE AT LANDMARK: 201 Yoakum Pwky. 1,600 units when finished next year. 37 acres. $90 million to construct. Owned by West Alexandria Properties, Inc., a subsidiary of Societa Generale Immobilaire of Rome.

Their oldest daughter is at college. Her sister will join her this fall. So last month, Marilyn and Paul Keller became former Mt. Vernonities. They bought a condominium apartment at Watergate at Landmark.

"We've done yard work for 23 years," Mrs. Keller said, as she carried cardboard boxes into her new home one recent afternoon. "We figure it's long enough."

The Kellers expected resistance from their children and amazement from their friends and neighbors when they announced their plans. Instead, they say they have gotten approval from the kids and envy from the adults.

What do the adults envy? "The feedom, mostly," said Marilyn Keller. "Here, you're buying amenities and life style. And everything that's outdoors is indoors - tennis, swimming, everything. In the winter, you don't have to go out. It makes it very easy."

The Kellers paid $75,000 for their two-bedroom apartment, which overlooks a small city park. The park was one of the things that convinced them. "It can't become something horrid," Mrs. Keller noted.

Their monthly payment includes the condominium fee, the principal and interest. It totals about $800 a month, the Kellers said. That is far more than they spent it Mt. Vernon, but then again, they made a handsome profit on the sale of that house.

In just the first few days of moving in, Mrs. Keller said she has discovered that it is easy to make friends - "much more so than in a single family neighborhood."

Her husband said he has discovered that it is both efficient and enticing to have so many recreational opportunities so close at hand. "A very small percentage of your non-working hours are available for recreation," he said.

Watergate's location was a major factor in their decision, the Kellers said. Both work in Rosslyn - he as a marketing manager, she for a graphics agency - and their commute will now be less than half as long as it was.

"There are a lot of things I'm giving up," Mrs. Keller acknowledged, as she gazed out into "her" park. "But look at this. Just look."

Martha Droge, 12, is doing lot sof looking as she sits in the Watergate courtesy bus. All day, it makes the round trip to and from Landmark Center. This day, it is 4:30 p.m. and Martha, enroute to buy a pair of jeans, is alone in the bus.

Alone. To Martha Droge, that is all too often the way she feels at Watergate.

"It has all the staff I like," she explained, as the bus began its run. "It's got a bike path around back, and there's the pool and the sauna.

"But I haven't met anyone else 12 or 13. There's lots of tinier kids 7 and under. There's lots of teen-agers. But all my friends are from school."

Even there, peace is sometimes hard to come by, especially since all her schoolmates understand the connotations of the name of her building.

"My friends at school get very unlight. They tease me about it, yes. But I think it's kind of dignified," Martha says.

Martha and her family used to live in a house in Arlington. Her parents separated last year. She lives at Watergate with her father and a brother, 14.

When the Drogers arrived at Building One in September, they were the 10th family to move in. Martha said she knows most of her neighbors, and more altogether than she knew in Arington. "But it is a little lonely sometimes," she said, as the bus stops in front of the Sears.

OAKWOOD: 140 S. Van Dorn St. 1,500 units. Rentals only. 36 acres. $26 million to construct. Owned by R & B Development, Los Angeles.

Mike Jarrett strode, barefoot, into the Rec Center pool room at Oakwood, a garden apartment complex that advertises itself as an enclave of "California-style" living for adults only (read swimming singles). He had been working out downstairs, and was dressed in grey sweatcloths.

"Been lifting weights," Jarrett said, setting down his grip bag and reaching for a cue. "Got a bad cold, so I sat in the sauna 45 minutes. No, I don't really feel any better."

But Jarrett, a radio-TV advertising accounts executive, felt well enough to shoot some pool and talk.

He racked up the balls, walked to the end of the table and fired the cue ball into the neat triangle. Good break.

"I'm an athlete, you see. Got athhlete's foot, so I must be an athlete," Jarrett chuckled.

"When I came up here two years ago from Roanoke, I asked all my friends where I could find the athletic facilities, the social climate and the luxuries I was used to. They all said Oakwood.

Jarrett delivered his testimonial in a dead monotone. He leaned over the green baize and pushed the cue forward. Click, click. The three ball fell into the corner pocket.

"Yeah, I like it here all right. I like the facilities."

They include the weight room, a pool, a sauna and an exercise room, and they are the reason Jarrett says he doesn't mind paying $425 a month for a two-bedroom apartment that's "like so." He holds his hand out to show its boxiness.

Jarrett is 31, and separated from his wife. She and their daughter live in Roanoke whila Jarrett tries to make it on the Washington singles scene. By his own account, he has mixed success.

But Jarrett seems determined. Small and compact, he keeps in shape with a vengeance. And there's a studied, tough-guy colness about him. He cups the chalk in his hand and turns the cue into it, just so, all the while studying the lay of the land on the pool table.

"I have met quite a few girls here. There's Happy Hour on Tuesdays. But a lot of girls shy away from it. Fifty girls and a hundred guys. I can understand their feeling that it's . . . well, sort of the local meat market.

"They have a Sunday brunch here, too. It's more low key. I meet more girls there."

What about friends?

"Well, Washington being the meltingpot it is .. . No, nothing super-close." A balls glides into a pocket.

"Well, got to run," Jarrett said, glancing at his watch. "My daughter calls me every Wednesday at 6:30."

For the first time, his face showed some animation. He pulled on two pairs of crew socks and his tennis shoes. "She was six years old on Sunday."

Chris Scheper is 29 years old. He and his wife split up a month ago. He decided to take the first apartment he could find. He found it thanks to the four-foot-high streamer across the top floor that reads "No Lease Required." In less than an hour, Chris Scheper had rented a $335-a-month, one-bedroom apartment at Oakwood.

By the time you read this, he will have moved out.

"It's a joke. It's a disaster," said Scheper. "They've createed what they call a marvelous social program. But I've never seen any of it.

"Yeah, my whole outlook is kind of jaundiced, I admit. But an apartment is an apartment. It's got a good refrigerator. That's about all I can tell you."

Scheper works at a gas station near the 14th Street Bridge, from dawn to dinner. That leaves little time or energy for the social and athletic opportunities at Oakwood.

"But even if I wanted, it would be hard here," said Scheper. "All you need to do is look in the parking lot." What he meant is that fully half the plates on any given day have been issued by states outside the Washington area.

Scheper has specific complaints, too. The hot water in the shower "disappears after ten minutes." The rent is "very high for what you get. Hell, my house payments were $315." And parking is sometimes nonexistent.

So Scheper has decided to move on, after only a month. At least there's no phone to have disconnected. He wasn't at Oakwood long enough to have one installed.

THE GREENHOUSE: 5300 Holmes Run Pkwy. 288 units. Approximately 8 acres. $14 million to construct. Owned by Inland Steel Development Corp.

When Majorie and Paul Leaf moved into their fifth-floor condominium in The Greenhouse in January, they caught a bad case of cabin fever.

"I kept feeling that I had moved into a luxury high-rise hotel furnished with my own furniture, and that I was going to pack my bags soon and leave," said Mrs. Leaf.

But the claustrophobia has gradually vanished. Now the Leafs say they have not only adjusted to life with elevators, balconies and sliding doors, but they like it.

"Of course, there are drawbacks to living in a high rise. But we didn't want to live in a house any longer," said Mrs. Leaf."We did that when the children were young."

"I've done the yard work bit," added her husband. "We both like to play golf. We have time to do that now."

Leaf is a scales representative for an office furniture manufacturer, and Mrs. Leaf is his assistant. They have turned one of their two bedrooms into an office, so they are able to commute to work most days in bedroom slippers.

When Leaf must call on clients, he says he likes the proximity of The Greenhouse to 1-95.

But location wasn't critical to the Leafs when they chose The Greenhouse. They liked the apartment layout, and the price was right.

"And I like the view," added Mrs. Leaf. Their apartment faces a brook and a wooded hill. "I didn't want to open my drapes and see Gino's."

The Leafs don't anticipate that high-rise living will change their life-style in any basic way.Mrs. Leaf said she does not shop at nearby Landmark Center any more than when she lived in eastern Alexandria. She said she still does her grocery shopping at her favorite Giant, on Route 7.

As for people, "Yes, we've met some very nice people going down in the elevator, but we've lived in the area several years," explained Mrs. Leaf. "We already have our circle of friends."

Shryn Powell is not new to the area, either, but she is at The Greenhouse because of a cactus. That and Uncle Sam.

Powell, 32, is a budget analyst for the Navy Department. She is single and lives alone. For five years, she rented an apartment just across 1-95 from Condo Canyon.

But "I moved into a salary range where I really needed a tax break," Powell said. And when she went shopping at The Greenhouse, they gave her a free baby cactus plant, just for coming.

"I just decided this was it," Powell said.

She bought a one-bedroom, 1 1/2-bath penthouse apartment. She put 10 per cent down, even though only five was required. She moved in around Thanksgiving.

Although she works at Crystal City, "I didn't really" consider buying there. "It's just too commercialized," Powell said. As for a conventional house, "I couldn't really see myself in one. I've been known to have trouble replacing a light bulb."

Nor did she "want to go to Manassas or something . . . . I like the area, and I liked these (apartments). They were brand new. So here I am."

She and about 150 plants, that is. The final nudge to sign on the bottom line was the 6-by-10 will plot on its front terrace that The Greenhouse will rent to any interested resident gardener for $10 a season. Planting time is upon us, and SharynPowell said she "can hardly wait." CAPTION: Picture 1, Golden McPeak: "It's got a good cross-section of people - retirees right down to young singles." By James A. Parcell - The Washington Post; Picture 2, Paul and Marjorie Leaf: "We didn't want to live in a house any longer. We did that when the children were young." By James A. Parcell - The Washington Post; Picture 3, Chris Scheper: "The rent is very high for what you get. Hell, my house payments were $315.", By Joe Helberger - The Washington Post; Picture 4, Martha Droge, 12, in the snack bar of the Watergate at Landmark., Photos by James A. Parcell - The Washington Post; Picture 5, Sharyn Powell: "I just decided this was it."; Map, no caption, The Washington Post