An Embassy Row butler wearing a dress hat and dark three-piece suit.

Chess players at Dupont Circle and prostitutes along Thomas Circle.

A flute player sending notes wafting to the roof of Union Station.

An elderly couple who have seen their Southeast Washington neighborhood change from all white to "all colored" and back again in the last four decades.

Scenes from Massachusetts Avenue.

For some, the name evokes an image of elegance and majesty -- a tree-lined boulevard of elaborate foreign embassies, of fashionable hotels and expensive homes.

To others, it is a kind of battleground -- a backdrop for their seemingly endless struggle against poverty, unemployment and increasing displacement by the affluent. It is the path to government-financed health care for the poor at D.C. General Hospital. It is the favorite route of the long, black limousines that transport the ambassadors of world governments to the White House.

The longest and most diverse street in Washington, Massachusetts Avenue stretches nearly 20 miles through Montgomery County and the District to the tip of Prince George's County, essentially besecting the city. Almost everything that is Washington, D.C., can be found from one end of the avenue to the other. It moves from the most economically depressed corridors of Southeast Washington, up the recently revitalized Capitol Hill, past Embassy Row and through some of the richest neighborhoods of upper Northwest and suburban Maryland.

Over the course of many days and nights, I walked the entire length of Massachusetts Avenue for a close look at people and places that I had seen before only through the windshield of my automobile.

Beginning at Southern Avenue in far Southeast, I followed the street westward. The first block is a good indication of the kind of diversity that characterizes the entire street. In the section between Southern and Alabama avenues, 80-year-old farmhouses, 25-year-old semi-detached homes, drab low-income apartments and attractive new town houses line both sides of the street.

On one side are a battered Volkswagen and an eight-year-old Oldsmobile. On the other are two new Cadillacs, a $36,000 BMW sports car and a Corvette.

Although Massachusetts Avenue is one of the city's most heavily traveled corridors, there are only two service stations on the street. There are two hospitals for people and one hospital for animals. There is one funeral home. There are no fast-food restaurants.

I saw all sorts of people. At 15th Street and Massachusetts Avenue NW one night, I listened to a dozen men quarrel at length about who would get the last swallow of a bottle of Boone's Farm apple wine that they had bought with a community collection.

In Dupont Circle another day, George Shepherd sat on the edge of the white marble fountain, playing a snappy tune on his harmonica for a lunchtime crowd.

Then there was the man who refused to be interviewed as he walked his small gray cat -- on a leash.

Although crime occurs anywhere throughout the area, the last slaying on the avenue took place two year ago at 13th Street, when a man was stabbed to death by a prostitute after he apparently decided not to pay her.

Where else can anybody walk off the street and into a palace such as the Anderson House at 2118 Massachusetts Ave. NW? The house, built at the turn of the century by the late U.S. Ambassador Larz Anderson and opened as a public museum at his death in 1937, is one of the largest and costliest homes in Washington.

The house has its original, custom-made furnishings -- huge crystal chandeliers; inlaid marble tiles; handcarved woodwork on ceilings and walls; millions of dollars worth of silver, ivory, crystal, gold and jade artwork, and priceless tapestries and paintings.

In Anacostia, tenants scramble from month to month to pay their rent; in Spring Valley, a mother of two complains that her maids will not allow her to help with the housework.

Where the avenue stars on the east, a middle-income resident can buy a spacious, three-bedroom brick house for just over $60,000. In affluent Montgomery County, at the other end, purchasers often pay between $225,000 and $250,000 for a house of similar size and quality.

Bethesda residents who live along Massachusetts Avenue have a choice of six bus routes that can carry them downtown during rush hour in less than 45 minutes. But bus service is spotty along the northeast and southeast portions of the street because the street is not as straight as it is west of Dupont Circle, according to a Metro official. East of the Anacostia River, there is no bus service.

At one end of the avenue is the House of Ruth, which houses homeless women. And on Embassy Row is the mansion of wealthy Texans Libbie and Clark Thompson. It sits almost unused six months of the year while the couple winters on the Gulf of Mexico.

Massachusetts Avenue, in most places a four-lane street paved with asphalt and concrete, was dedicated in 1796 as part of Pierre L'Enfant's original city layout. The street, originally only 4.3 miles long, stopped at 19th Street on the east and Florida Avenue on the west.

Through a series of later extensions, the street finally reached to Southern Avenue on the east and Westmoreland Circle on the west in the District, and beyond that to Goldsboro Road in Montgomery County.

Just 35 years ago, hunters bagged squirrels and rabbits in the thick woodlands, and children picked wild berries on the spot where Massachusetts Avenue now intersects Southern Avenue at the District of Columbia-Prince George's County line.

In those days, Massachusetts Avenue stopped at Alabama Avenue, and the few people who lived along the small, narrow road enjoyed the slow pace of country living.

Rufus and Catherine Dillard, both 64, still remember the old neighborhood where they raised five children in what was then called "deep country," just inside the city limits.

Today, the Dillards live in the two-story house they have rented for basically the same price since 1950. The small wood-frame dwelling sits on the last remaining strip of the old country road -- Boulevard Place -- in the shadows of a huge, silver-painted steel storage tank, which contains the emergency water supply for D.C. residents east of the Anacostia River. Boulevard Avenue was closed permanently in the early 1950s, when Massachusetts Avenue finally made its way to the county line.

Along the wide street, lined with elms and maple trees, is a mixture of modern suburban-style houses with neatly trimmed lawns, low-rent apartment duplexes, semi-detached homes and new town houses. Even during the rush hour, the flow of traffic is light on this end of the avenue.

"Back in the '40s," said Catherine Dillard, "we didn't have running water or indoor toilets. It was just plain country living. I remember when the family across the road raised hogs and killed a few of them every year for a fresh supply of meat."

It is known worldwide as Embassy Row. It extends just two miles, from 16th Street and Scott Circle NW to the intersection of Wisconsin and Massachusetts avenues. Some countries pay fabulous prices to locate their embassies on the strip. Others pay nearly as much for space on side streets. The Canadian and British embassies have the largest amounts of office space on the strip.

As a result of the hostage crisis in Iran, that country's embassy -- which under former Ambassador Ardeshir Zahedi was one of the notable party sites in Washington -- has been ordered closed by the U.S. government and one of the embassy's buildings on Massachusetts Avenue is boarded up.

Embassy Row is not only for glitter. At the newest embassy building in the city, New Zealand Ambassador Frank Gill and his wife, Barbara, played host one recent night to the Friends of Handel, a local group that promotes live performances of classical music.

The mile-long stretch of Massachusetts Avenue on the southern edge of Fort Dupont Park SE is probably one of the city's most ideally situated communities. Residents have easy access to downtown shopping and jobs, and can retreat to the solitude and pleasant scenery of the 376-acre park.

Joseph Dodson, 83, and his wife, Willie, 82, built their handsome English-style home across from the park 23 years ago with the hope that the nature of their neighborhood would not change.

While some other parts of the city have undergone dramatic changes over the last two decades, the Fort Dupont Part community has remained relatively stable. Adjacent to the Dodsons are five other houses built about the same time as theirs and the huge, red brick Fort Dupont Park Seventh-day Adventis Church. Farther down the hill, toward Randall Circle, are two dozen contemporary-style homes, built mostly since the mid-1960s.

Paul and Carrie Pope spend a lot of time just sitting on the front porch of their huge three-level row house at 18th Street and Massachusetts Avenue SE, watching the steady stream of cars, ambulances and police vehicles move in and out of the grounds of D.C. General Hospital, the city's hospital for the poor, and in and out of the new D.C. Jail.

The Popes, both in their 70s, remember when the hospital complex consisted of one building, when there was only the ancient D.C. jail, and when the site where their house stands was a cow pasture.

Back then, Massachusetts Avenue was a dusty road that edged its way around the pasture and onto the hospital grounds, where several small "TB" houses had been erected for victims of tuberculosis.

"There was a huge hill in the middle of the grounds where the hospital superintendent lived in a very large house and kept two pet bloodhounds," recalls Pope, a retired federal employe.

"We sat on our porch and watched the old wooden railroad bridge burn," he said. "We have watched the D.C. Jail guards chase escaped prisoners down the street. And we watched them put in the subway station."

The Popes said they have also seen their neighborhood go from all white to nearly "all colored" to a diverse mix now of both black and white homeowners in the 45 years they have lived there.

Over the past decade, the most dramatic change along some parts of the avenue has been in its racial composition.

"When I opened my business here in 1956, this neighborhood was about half white, half black," said Marquette Pierce, owner of the popular Pierce's Bar and Grill on the southwest corner of 15th Street and Massachusetts Avenue SE. "In the early '60s, most of the white families moved to the suburbs and left the community almost all black. But since 1976, we have seen more and more white families moving back."

Pierce said that 10 white families have moved into one block near his bar, and 20 white families have bought homes in another block within the past two years.

Pierce and other black merchants in the small commercial enclave contend that rapid changes in the community have resulted in new efforts by real estate speculators to entice struggling black business owners to sell.

"Almost every day, another [speculator] sticks his head in the door and asks if I'm ready to sell my bar and grill," said Pierce, 59, who said he has been offered $125,000 cash for his business. "I tell them they're crazy and that I'll never sell.My family has operated a business in this city since 1939.But the real estate people keep coming. Sometimes they go door-to-door, offering to buy peoples' houses on the spot."

On another corner, the aroma of hot barbecued chicken permeated the chilly night air. But the crowd of men huddled together near the entrance to Sonny's Wings seemed more interested in the wine bottle they were passing around. Inside, another group of men stood with their hands in their pockets -- smoking, talking and soaking in the hot steam of the deep fryers. But not many people were spending money for Sonn's southern-styled barbecued chicken and ribs.

"I'm just doing all I can to hold on until the community changes a little more," said Sonny Burton, 43. "These guys are good people. But a lot of times they are out of work and don't have the money to buy anything. But I manage to make enough money to pay the employes and keep up my taxes."

A year ago, Burton quit his trash collection business and paid $1,500 for a barbecue chicken carryout near 15th Street and Massachusetts Avenue SE. The price was right, the location was perfect, and Burton felt he finally would get a chance to test public reaction to his "Mumbo" sauce, a thick, brown sauce he said he first made with a secret recipe when he was 18. Since he opened shop, Burton said, he has worked 14 to 16 hours a day, seven days a week in a struggle to develop his business.

Earlier this year, Burton said, he lost business when a Korean opened an Oriental carryout across the street. He expects to lose even more business early next year when a 7-Eleven opens three doors from his shop in an abandoned pool hall purchased recently by another Korean investor. Both developments are examples of a trend that has been occurring elsehwere in the city.

As Burton talked, two white women picked their way through the crowd of black men in front of Sonny's, walked up to the counter and ordered wings. Within minutes, they were on their way out.

"I'm glad to see I'm getting some of the new neighbors," Burton said. "I once asked those ladies why they go through all that to come into my place. They said they keep coming because we sell good wings."

Robert Herrema stood in front of an old five-story apartment building at 11th Street and Massachusetts Avenue SE near Lincoln Park and gazed toward the building's top floor.

"It's as solid as a rock," he said. "A very sound building, built at the turn of the century. There are no signs of erosion in the mortar, but we'll have to replace the roof."

Six months ago, Herrema and his business partners bought the building, formerly known as the "Alcazar," and began to renovate the handsome beige brick structure. Three years ago, a dozen low-income families lived in the then-rundown building, which has been redesigned into nine condominiums that could cost more than $100,000 each when they go on sale early next year.

Herrema, a former Senate administrative aide, now renovates houses and buildings in the Capitol Hill area. Five years ago, he moved his wife and two girls from their large house in Potomac to a 113-year-old town house at Lincoln Park.

"A lot of the best houses have just been left over the years to rot," Herrema said. "I feel good when I can restore a house and breathe new life into the community."

The 10 blocks from 11th Street SE to Stanton Park, near Union Station, present a dazzling display of homes. Many have been fully restored during the last 10 years and restoration is in progress in numerous others. The Stained glass, gleaming brass doorknobs and light fixtures, newly installed windows, and iron gates and fences have brought new sparkle to a community that was once on the decline.

Stanton Park has become a favorite site for corporations that want to be closer to the federal legislative complex just five blocks away. Many of the tattered apartment buildings and rundown houses that used to ring the picturesque park have been renovated in recent years into attractive office complexes.

The Heritage Foundation, the conservative policy think tank, has spread its offices into three buildings on the southeast edge of Stanton Park. The organization started out inthe old Stanton movie theater, then grew into the adjoining building, formerly used as a Korean delicatessen. Earlier this year, the foundation added the adjoining three-story town house. The house was used as a halfway house for convicted felons returning from prison, until it was renovated and occupied by the foundation.

William Connell moved his firm, Concept Associates Inc., into a newly renovated red-brick town house in 1976 to be closer to his Capitol Hill clients. The company primarily makes political campaign films and documentary films on such subjects as drug abuse.

Connell's offices, at 420 C St. NE, are adjacent to quarters occupied by an assortment of special interest groups and private corporations that include the National Christian Action Coalition, the American Legislative Exchange Council, the Christian Voters Victory Fund, Christian Voice, Christians for Reagan, and Political Communications, Inc.

Late at night, the gigantic granite structure looks a lot like a mausoleum. It is dramatically bathed in floodlights. For long periods, there are no signs of life.

Then there is the faint hum of a locomotive and a porter bursts through the double doors with a sleepy passenger's luggage. This is Union Station, the city's historic and controversial train station, now serving double duty as a national visitors' center. The red-brick promenade in front of the huge 70-year-old building is decorated with marble fountains and statues. There is a rose garden, and massive flagpoles.

A walk through one of the three huge Roman arches leads into the main concourse where six derelicts lay sprawled on the gray marble floor, asleep.

In the background there is the sound of music -- a strange vibrating music that could easily be the score for a mystery movie. But it is the flute music of Maha Fahim Ruba, a D. C. musician who said he is rehearsing at Union Station for an album he plans to record next May at the Taj Mahal in India.

Ruba, a native of Katmandu, Nepal, said the high, arching ceiling of Union Station is the closest comparison in the United States to the Taj Mahal, where the ceilings are even higher. And so at night, when he is interrupted only occasionly by passengers, Ruba rehearses. The sounds he plays bounce delicately off the ceiling and create a soothing melody.

His audience consists of the derilicts, two employees waiting to help travelers with their luggage, and 36 life-sized, stone statues that stand silently in their places on ledges around the ceiling.

Two sides of inner-city life convergeat Thomas Circle. One day recently, prostitutes strolled on one corner while worshipers across the street made their way to services at the National City Christian Church. Homeless men and women waited for alms on the back steps of Luther Place Memorial Church, and nursery school children crossed an intersection behind their teacher like so many ducklings in a row.

But unique among its Thomas Circle neighboors is Thomas House, a four-year-old housing complex for senior citizens. The 10-story building, owned by the Baptist Home of Washington, is a self-contained community of 165 residents. It includes a small shopping area, a sundeck with a barbeque grill, a rooftop swimming pool, beauty and barber shops, a recreation room, and a 50-bed hospital unit.

For the senior citizens who can afford it Thomas House provides a comfortable life style, where personal service and security are plentiful and pocketbook snatchings are rare.

"Our building is not for the infirm, but for older people who are independent and enjoy living in the heart of the city," said Deidre Rye, assistant administrator of the building. "Most of our residents are 'hard core' downtown Washingtonians who have retired from the federal government. They moved to the city 30 or 40 years ago to work and have no interest in living in upper Northwest or in the suburbs."

Perhaps the most popular apartment house in downtown Washington is the 556-unit complex at 1500 Massacusetts Ave. NW. Built in 1952, the building which consists of 446 effieiencies and 110 one-bedroom units, was designed for transient residents and government employees who wanted quick access to jobs a few blocks away.

"When the building opened, this was the place to live," said Richard Calabria, the general manager. "At one time, we had a uniformed doorman to hold the door for residents and to help them with luggage and packages."

The chivalrous doorman has long since been replaced by a rather ordinary, coded telephone entry system. But 1500 Massachusetts Avenue has remained popualr over the years. Nearly a third of its current residents have lived in the building since it opened, and the monthly turnover rate is less than 2 percent, Calabria said.

Although Pierre L'Enfant planned no distinct role for Massachusetts Avenue in his layout of the capital city, the street began to develop as the "grand avenue" of the District of Columbia in the 1870s during the administration of the appointed D.C. governor Alexander Robey Shepherd.

It was with the major development program initiated by the Shepherd administration that Washington, for the first time, began to look like the nation's capital.

Shortly after taking office, Shepherd announced a major property tax increase, the proceeds of which he used to pay for the paving and grading of city streets, improved lighting and the planting of thousands of trees.

The centerpiece of his efforts became Massachusetts Avenue, a street whose beauty and accessibility made it a very desirable place to live.

Many wealthy Washingtonians chose Massachusets Avenue in the early 1900s as the site for their large, expensive and sometimes pretentious residences. Mary Foote Henderson, who built a castle on a hill just north of Massachusetts Avenue on 16th Street, launched a campaign to persuade her well-to-do friends to build near her expensive home. Some did. But most preferred the attractions of the avenue.

Since he was 21 years old, John McCullough, now 67, has enjoyed the trappings of wealth -- the fine foods, expensive automobiles, lavish houses. He has joked with the rich, exchanged thoughts with world leaders, and mingled with the jet set.

McCullough, whose mannerisms are those of a man of means, is a butler, a chauffeur, a hired servant.

He works for retired Texas congressman Clark W. Thompson, 85, and his wife, Libbie, 84, who inherited the $400 million fortune of her father, William L. Moody, when he died in 1954. That same year, the Thompsons built their mansion, dubbed the "Texas Embassy."

Early on weekday mornings, McCullough -- a tall man, impeccably attired in dark three-piece suit and dress hat, with a gray tint in his hair -- can be seen driving along Massachusetts Avenue in a long, sleek, sky-blue Cadillac. He pulls into the driveway of the handsome, red-brick mansion as though it were his, parks in a favorite space and disappears inside.

"A lot of young people say they wouldn't be a butler. They've called me a flunkie," said McCullough, now down to his white shirt sleeves, watering plants in a quiet, pale-blue drawing room. "But it's not a matter of being a flunkie.It's a job. At least, when I work for millionaires, I have somebody who can do me a favor if I need it."

McCullough said that his daily duties for the next few months will consist of such things as watering house plants, dusting furniture and assisting the maid and the gardener.

His employers are in Galveston, where they spend the winter months at their villa on the Gulf of Mexico. In the fall, McCullough said, he drives the couple the 1,622 miles from Washington to Texas. Then he flies back to Washington to resume his butler duties. In the spring, McCullough returns to Texas by jet and chauffeurs the Thompsons back to Washington.

"I've learned over the years that you can learn a lot from rich people if you just be quiet and listen," McCullough said. "You know exactly what's going on in the world because you get it from the horse's mouth."

"But I don't think I'd like to be a millionaire," added McCullough, who said he earns $12,500 plus keep as a butler. "They have a lot of problems and not much privacy. They've always got to have somebody watch what they got to keep somebody else from stealing it."

"Massachusetts Avenue was nothing but a dirt road when my father started building out here," said Edward Miler, 55, as he inspected a group of new and expensive townhouses in Spring Valley, one of the city's 10 most expensive neighborhoods. "This area was all farms, and we used to ride horses through here."

Miller, now president of W C & A N Miler Development Co., and his father built many of the houses that helped transform upper Northwest Washington and parts of Montgomery County from rugged farm communities to fashionable neighborhoods for the well-to-do.

"When we planned these houses in 1973, we expected to sell them for a top price of $85,000," said Miller, referring to the 24 new townhouses he is building. "One of these houses just sold for $249,500 and another was sold for $254,500. Our houses are built well. Most of our craftsman have worked for us a long time and they still take pride in their work."

The largest remaining tract of undeveloped private property within the city is 43 1/2 acres, between 49th Street and the Dalecarlia Parkway, near Massachusetts Avenue in Spring Valley.

Miller said his firm, with its 200 skilled craftsmen, will build a new community of single-family homes and a shopping and office building complex there over the next 15 years.

Until 1937, a large section of the city's northwest side was bordered by nothing but woods. But then Massachusetts Avenue was extended into Montgomery County -- and not far behind came the developers.

Today, the 2.3 mile stretch of Massachusetts Avenue that extends from Westmoreland Circle to Goldsboro Road is one of the prime high-speed commuter routes into Washington from the Maryland suburbs.

Twenty years ago, the street was widened to four lanes to make way for the traffic from new developments in Bethesda and Potomac that now jams the avenue during morning and evening rush hours. Bus service on the avenue is among the city's best. But pedestrians who attempt to walk along those sections of the street where sidewalks are absent risk being run down by speeding commuters.

"We love the avenue because you have the feeling that you're a part of the city without actually living within the city limits," said Frances Wylie, who lives just off Massachusetts Avenue near the Glen Echo fire department. w"The biggest problem around here is the trucks hauling earth from excavation sites. Sometimes you may have 20 big trucks an hour rumbling down the street. sIn the summer, the trucks never seem to stop."

Bruce K. Baumgardner, president of the High Point Citizens' Association, near the tip of Massachusetts Avenue, said: "I think the real problem is that this community has always been shortchanged. We've had the problem with the trucks. A community like this should have had public swimming pools years ago. But we just got our first this summer."

Baumgardner's neighbors also have been plagued recently by burglaries. About 60 residents met with Montgomery County police last month to discuss 13 recent late-afternoon break-ins in which burglars took silver, art objects and other valuables.

When Arnold Davis drives his Metrobus along the northwest end of Massachusetts Avenue the doctors, lawyers and government workers who are his passengers sometimes ask where he lives.

"I tell them I own my own home on Massachusetts Avenue and they don't believe it," said Davis, 32, who earns $20,000 a year. "They say they don't see how a person with my income can afford to live in a neighborhood where houses cost $200,000 or $300,000.

"Then I Explain that I'm not referring to the Northwest end of Massachusetts Avenue, but to the Southeast end across the Anacostia River, where I grew up," Davis said. "Most of my passengers are not too familiar with my neighborhood. And I probably would have never visited the upper Northwest end, if I didn't drive a bus."