Old Town Alexandria, a unique part of Washington's suburban ring, is taking off.

The charm and desirabililty of its hundreds of 17th-and 18th-century homes and commercial buildings set off a massive renovation effort in the 1960s that is still going on. Since then, a host of other factors have combined to generate a development scramble that is proving to be a gold mine for the city and, until last year's soaring interest rates hit, for the developers, too.

The foundation of it all remains the concentration of old and historic structures that is hardly matched even in colonial cities such as Boston, Philadelphia and Charleston, or in Georgetown. The buildings provide an ambiance that attracts tourists, shoppers, would-be residents and variety of businessess, including a burgeoning number of restaurants.

The Old Town aura was no small factor, for instance, in the decision by Time-Life Books to move there from New York 4 1/2 years ago. There are now 41 trade associations with headquarters in the city and more on the way, city officials say. And the rapid growth of the number of speciality retail stores along King Street has given the area some of the characteristics of a regional shopping center with many of the customers coming from outside Alexandria.

Ambiance is hardly the whole story, however. The continued energy crunch, expected Metro service next year, proximity to National Airport, a surprising amount of vacant or underutilized land -- even the end of Virginia's prohibition of sales of liquor by the drink -- have all contributed to the resurgence of Old Town.

But developers building anything other than Federal-period town houses have not been greeted with open arms by most of the residents of Old Town. The citizens repeatedly have blocked projects or forced them to be scaled down. High-rise buildings have been a particular target. While some members of the Chamber of Commerce have dreamed about Crystal City clones on the edges of Old Town, the residents have been clamoring for building height limits, down-zoning and parking restrictions.

There have been bitter complaints about parking and traffic problems associated with the expansion of stores and restaurants in the area along or close to King Street just up from the Potomac. The dozens of boutiques, gift shops, galleries, other stores and restaurants are cheek-by-jowl with $250,000-plus homes. Complaints by residents of rowdiness and drunkenness on the part of restaurant customers brought a police crackdown and a new ordinance requiring a special-use permit for operating a restaurant in the city.

Now there is a new acrimonious dispute between city officials and the mostly black residents of two large town house-like public housing projects in Old Town over proposals to build new units on the same sites. Officials say the 40-year-old projects are deteriorating, and they would like to replace them with higher-density units, freeing part of the extremely valuable land for private development. The residents fear they will lose their homes, a formal commitment from the city to maintain the same number of public housing units notwithstanding.

The value of Old Town land, and of its buildings, is a major part of the Alexandria story-between 1970 and 1980. In the decade, real estate assessments for the entire city of Alexandria rose from $892 million to $3.2 billion. The roughly 950 acres that lie between the Richmond, Fredericksburg & Potomic Railroad traks and the Potomac Rivers -- an area that encompasses Old Town, the precise boundaries of which partly in the eye of the beholder -- accounted for less than one-foruth of the 1970 total. By last year, despite substantial construction of towering condominiums in the western end of the city, the value of real estate east of the railroad was approaching one-third of the total.

Tiny two-bedroom town houses regularly sell upwards of $100,000 in the heart of the Old and Historic District. More than a dozen private homes now are assessed for more than $500,000, and one recently sold for three-quarters of a million dollars.

One of the most remarkable parts of the development story is the willingness of homebuyers to pay very high prices for houses in location that normally would be considered undesirable. On Union Street, two blocks south of King, new town houses under construction are selling from $191,000 up to $400,000. They are only one block from the river, but the view is completely blocked by the blank walls of an Interarms Co. warehouse.

Ten blocks from the river, along the very heavily traveled Route 1 corridor of Henry and Patricks Streets, new town houses also are sprouting, and renovation of other rundown homes is under way. There, however, the Braddock Road and King Street Metro stations, set to open in late 1982, are only a few blocks away, evidently enough of an attraction buyers' minds to offset the constant roar and smell of cars and heavy trucks.

Metro, too, is the prinicipal reason ground will be broken late this year for the first phase of a major office and retail development planned by the Oliver T. Carr Co., the Equitable Life Assurance Society of the United States, and members of the family that formerly owned the land on Duke Street only a few hundred fet from the King Street station. The first half of the 300,000-square-foot project will be ready for occupancy in 1983.

Developer Oliver T. Carr says the site is, of course, anchored by the Metro station but also notes that renovation and redevelopment of King Street is spreading steadily from the river's edge toward the new station.

"Architecturally, we will do everything we can to make it [the project] harmonious with Old Town," Carr promises, implicitly ackowledging that the Old Town aura is a strong selling point. Carr is pleased with the way the city government has moved to "control growth and the quality of it."

Carr has no problems with a 77-foot height limit the City Council imposed in the area not long ago under pressure from nearby residents, but landowners at the time warned that lowering the limit from 150 feet would prevent just this type of project.

Mayor Charles Beatley is very proud the city has responded to development pressures by, as Carr puts it, controlling growth and the quality of it.

"In Arlington, the business community has run roughshod over the residents" in allowing construction of the Crystal City and Rosslyn complexes, Beatley declares. "We have not lost our identity, and we have gained from it . . . And I think business has been happily surprised at the results." On the other hand, backers of faster growth point out that Arlington's property tax rate is more than 20 cents per $100 less than Alexandria's $1.39. p

The tensions of development still abound, however. For instance, Roger Mechanic, whose Development Resources Inc. is building new town houses and converting older garden apartments to condominiums on the northern edge of Old Town, says he hopes the city finally has begun to think more constructively about allowing major development rather than simply opposing it.

Clifford Rusch, the deputy city manager who has been in Alexandria since the mid-1960s, says the city has followed a "consistent strategy" of seeking primarily new office structures to be occupied by trade associations and similar groups. The buildings add to the tax base, and the office workers become customers of the retail shops and restaurants. At the same time, the revitalization of the residential property is encouraged.

If the city had had the money in the 1950s or early 1960s, Rusch says, much of Old Town might have been wiped out by massive urban renewal projects, both public and private. But it did come gradually. Now, with the height limits and formal restrictions on all 100-year-old structures -- which are virtually all protected by city ordinance from demolition or even "inappropriate" external changes -- Rusch is confident "we are not likely to get anything to overwhelm the balance."

"It's Old Town that gives this city an identity, a pizzazz the ordinary suburb doesn't have," he declares.

Ambiance, pizzazz, location. It still took years to get Old Town fully off the ground. Taylor Burke, president of the Burke & Herbert Bank and Trust Co., the city's only remaining independent bank, recalls that the 400 and 500 blocks of King Street looked like "the Great American desert" after urban renewal wiped away several square blocks of old buildings. "It sat vacant for years. No shops, no people," he says.

As the new building rose, they still had unoccupied office space for years more. Finally they are fully rented, the Old Town Holiday Inn on one of the blocks has high occupancy rates, and the city itself is just finishing a combination couthouse and office building in the 500 block.

Burke's own business, the bank, has grown along with Old Town. After several decades of virtually no expansion, the bank began to increase its assets in 1963, Burke says. In the past 10 years its size has nearly quadrupled, reaching assets of $87 million last year.

Burke says that for all of the now successful local development, Alexandria is still in many ways a bedroom community for Washington, that the high salaries of government employes, lawyers and others working in the central city have paid the way for Alexandria's residential renewal. Nor is he all the sanguine about the apparent success of the myriad stores and restaurants in the King Street area. For one thing, he says, the rents are sky-high.

"Those stores don't support the owners, they support the landlords," Burke maintains. "These little businesses are paying from $12 to $15 a square foot, and at the end of the year they have just abut paid the rent."

But Burke doesn't think the landlords are ripping off the tenants, rather that most of the landlords paid outrageously high prices for the buildings. One such building, a beautiful four-story brick town house in the 200 block of King known as the Gilpin House, is on the market for $1.4 million. In the 100 block, a former small warehouse building is for sale for $800,000. Mayor Beatley fears high rents and parking problems could leave the Old Town with nothing but "a sea of office buildings," and he has asked for a study of the problem.

Each time a store or a restaurant closes, rumors fly about the cause. Last month a Hahn's shoe store in Washington Street near King closed but not because business was bad, it turns out. Rather, the building's owner would not renew the lease because it is on the market, and Hahn's, which owns none of its store locations, was not buying, a company official says.

Some of the more successful stores are protecting themselves by buying their buildings. with high-quality clothing and a wide range of other merchandise such as doll houses and miniatures, have bought a half interest in their building on the corner of King and Lee partly to gain room for expansion.

Why Not was a pioneer operation, opening 17 years ago when the area was, as Jeanne Graef, one of the founders, recalls, full of "pawnshops and billiards parlors." Today, Loti Dunn, another partner, declares, "It's the best place to do business in Washington. It has a neighborhood character, but a metropolitan character, too."

The customers generally are affluent, because the specialty merchandise in most Old Town shops is not cheap. They come from Alexandria itself but also from McLean, Bethesda, Chevy Chase, from all parts of the metropolitan area. And more recently, business executives who have been in Old Town for meetings at trade association headquarters or other offices are buying presents to take home, the shop owners say.

Tourists, too, are coming in increasing numbers, drawn by Old Town's historic attractions. The Alexandria Tourist Council had 122,000 people drop by its visitor center in the Ramsey House at King and Fairfax streets, a 24 percent jump over 1979, according to Barbara Janney, the council director. She estimates that six or seven times that many tourists actually visited the city.

For many of the merchants, and for the Tourist Council, perhaps the greatest worry these days is parking. During weekdays it's no problem since enforced three-hour parking restrictions in surrounding neighborhoods eliminated most commuter cars. But it is difficult for people working in Old Town and for anyone on weekends. Late this year it will get worse when demolition begins on one of the old World War I torpedo factory buildings just off King Street that now has 150 parking spaces in it. The demolition is part of another development that will include 99 new condominium units, a 440-space parking garage and significant amounts of office space.

Other imminent developments, such as another 75,000-square-foot office building on Duke Street not far from Carr's project, Savage/Fogarty Co.'s Trans Potomac plaza on North Fairfax Street -- a 175,000-square-foot building near the Eisenhower Avenue Metro station that will house the American Trucking Association -- all will add customers to Old Town's shops and restaurants, and cars to the streets.

Meanwhile, high interest rates and a shortage of mortgage money finally have slowed at least temporarily the astrononical rise in the value of much of Old Town's real estate. Also, new town houses have been built faster than the market could readily absorb them. But most of the developers see this as a temporary setback. For instance, Rodger Digilio, head of OTV Inc., who has a reputation for quality renovations of older structures, has several projects waiting, in effect, for lower interest rates.

Overall, the city's development strategy clearly seems to be working. The constant tension that arises from the basic goals of the strategy, however, remains. As Deputy City Manager Rusch notes with some feeling, "This mixed-use concept is not an easy chemistry to manage." CAPTION: Picture 1, Shoppers stroll past the shops, galleries and cafes of lower King Street Saturday. By James A. Parcell -- The Washington Post; Picture 2, This large home at Cameron and North St. Asaph, with its distinctive double staircase, recently sold for $750,000; Picture 3, Gilpin House in the 200 block of King is on the market for $1 million to $1.4 million.; Picture 4, Among first new town houses in Old Town, this complex is on North Union at Founders Park.; Picture 5, These $190,000-$400,000 town houses in the 300 block of South Union face a brick warehouse wall.; Picture 6, United Way will move from building in background to new HQ on this site on North Fairfax. Photos by M.C. Valada for The Washington Post