They give the most exclusive tours in town.

In Alexandria they might rent a minibus for a group and stop to take the group to lunch with the mayor in Old Town. In Arlington they play up the county's 10 Metro stops, whisking visitors in minutes from Ballston to Rosslyn to Crystal City. And in Fairfax County they sometimes use the prospects' own limousines to cruise from Dulles to Reston to Tysons Corner.

These tours aren't available to just anyone. They're for the big spenders -- businesses and corporations that have shown an interest in relocating in Northern Virginia, moves that would create a wealth of new jobs and broaden the tax base, pumping millions of dollars into the community.

The people who conduct the tours are city planners, Harvard MBAs, former real estate brokers and economists who, armed with stacks of facts, analyses, maps and slick color brochures, staff the area's economic development offices.

"We're here to create the context for growth," said F. Daniel Montague, director of Alexandria's Economic Development Program. "It doesn't just happen. Our office is a catalyst in creating the attitude, interest and enthusiasm and then helping find the space for people to locate here. We must define what we have here and sell what this is."

Loudoun County's Department of Economic Development calls itself "the county advocate for business."

Giving tours is just a small part of the work. The real job is to package and market the city or county -- working with companies interested in moving there, seeking out new prospects and getting them interested in what a particular jurisdiction has to offer and sometimes helping businesses already in the jurisdiction with expansion plans.

The recruiting methods and resources are as diverse as the areas themselves.

The Fairfax County Economic Development Authority is the big kid on the block. Its widely acclaimed efforts, which have helped lure giants like Mobil Oil Corp. to Fairfax, will spend close to a million dollars this year on a razzle-dazzle program that last year attracted 12,000 inquiries from businesses about the county.

"Everyone is impressed at the quality of life here," said Fairfax County Board Chairman John F. Herrity. The Fairfax ads say, "When you look at Washington, the view is better from Fairfax County, Virginia."

Northern Virginia's proximity to the power of Washington apparently lures many businesses to the area.In Arlington, office space totaling 2 1/2 millions square feet was constructed in 1981, according to statistics just compiled by development specialist Jocelyn Holland. "Arlington, Virginia," says the office logo, "Close to the heart of Washington."

And Alexandria, which has $200 million in new construction now in the works, advertises that it's "closer to National Airport than Washington itself."

"Our federal relations people must have access to Capitol Hill," said Don E. Blom, associate executive director of the National School Boards Association, a District-based association that is considering a relocation, possibly to Alexandria. "So that puts limitations on where we can look."

The National Milk Producers Federation is constructing its own building near the Arlington Court House and plans to move its District office there in June. "The basic reason is Arlington's proximity to the northwest quadrant of Washington and proximity to the Department of Agriculture," said David Gillam, director of financial management for the national trade association. "Plus there is Metro."

Nearness to the District isn't the only selling point. Economic development officials also point to the availability of office space, a good supply of labor, affordable housing in some areas, proximity to airports, availability and price of land and quality of education. But there are significant differences in what the local jurisdictions have to offer businesses and what resources they have to encourage movement to their area.

Besides recruiting businesses to their jurisdictions, the development offices also help smooth the way for the companies' moves -- which can include helping them with financial arrangements, primarily through low-interest loans funded by revenue bonds, although the extent of this help varies.

In Alexandria and Arlington, the low-interest loans are approved by an industrial development authority that's separate from the development office. But in Fairfax, the development office is part of the authority rather than being a direct part of the county government, which means that the office that recruits a company is the same office that determines whether a company is eligible for a special low-interest loan that can facilitate the company's move.

Observers also say this separation from the county government gives the Fairfax development office more independence, even though it is funded by the county government through normal budget procedures.

Some county supervisors, such as Audrey Moore, would like more control over the authority. But Herrity said he's satisfied with the arrangement and thinks the million dollars is well spent.

"I think we have had an aggressive, hard hitting economic development program, and I think we ought to continue in the same direction," said Herrity. "I think the bottom line certainly indicates that the results are worth a lot more than a million dollars. You don't give them a couple of nickels to go out and do that job, nor do you look over their shoulder all the time. You look at the results.... People on the board complain about economic development, but you go to Cleveland or Detroit and look at what those people are getting."

Fairfax has a staff of 14 with elegant offices in the shadow of Tysons Corner, the wizardry of a computer data bank and a fat directory of business and industry already established in the county. Its sophisticated advertising campaign has an annual budget of $355,000 and regularly features full-page ads in the Wall Street Journal, Fortune and Forbes.If you call to say you're going to stop by for some information on the county, a staff member asks in jest, "Do you have a pickup truck?"

David A. Edwards, who has been the executive director of the authority since 1974, announced in November that he would resign in May. Edwards has watched the authority quadruple its budget and staff between 1978, when the office began to expand, and 1981. Fairfax's hardhitting advertising campaign started with a bang with a full-page ad in June 1978 in the Wall Street Journal.

And Fairfax officials say that from July 1, 1980 through June 30, 1981, their efforts helped bring 51 companies with 3,475 new jobs and almost $4 million in estimated annual local tax revenue to the county.

Hugh Keogh, director of marketing and communications for the Virginia Division of Industrial Development, said the Fairfax program has the biggest budget in the state.Fairfax has $943,000 to spend, compared with the state office's budget of $2.5 million dollars. Keogh also called the other local offices "first-rate."

"The quality of programs regionally in Northern Virginia is stronger than (in) any other region of the state," said Keogh.

Thomas C. Parker, director of Arlington's economic development division, says his county doesn't do much actual recruiting. In fact, the majority of the work in most of the development offices is liaison work with companies that already have shown an interest in a particular area.

"The locational advantages here and the Metro service, with 10 stations already open, has produced a strong demand within the development community for sites," said Parker. He points in particular to the 146 office buildings in the county and the new 30-story twin Arland Towers buildings, which have attracted clients like Bendix, Northrup and Gannett.

The Arlington office, with seven people assigned to business development, is relatively new as a separate entity. The office, with a budget of $318,000, was broken off from the county's planning office last February. It has a special projects officer who concentrates exclusively on major efforts such as the Rosslyn-Ballston Metro corridor, particularly the planned Court House Plaza.

Alexandria has $90,000 to spend on recruiting and a staff of two, whose office is at the Chamber of Commerce. The office is funded half by the city and half by the Alexandria Industrial Development Authority, from fees paid for industrial bonds.

"We're the smallest program but the most dynamic," said Montague. He said the program began last July so the city could compete with other jurisdictions in the development arena. "Right now our data is in my head and in the bottom drawer," he said. It has no advertising budget. "This first year, we are building our base of promotional materials," he added.

Nearby Loudoun and Prince William counties play the recruiting game too. "We are a much better bargain," said David Dodd, Prince William's director of economic development. "We can give you more bang for your buck."

Prince William has had a development office since 1977 to help as the county began maturing from a rural to a more urban area, said Dodd. County officials boast of their spacious industrial parks, rail connections, interstate highways and lower land costs. "We have livability and prestige," said Dodd. "We're i the middle of the hunt country, an it's really a classy location. It's a outstanding opportunity at an acceptable cost."

The Prince William office, with $165,000 budget, has just hired John Gessaman, formerly with the Arling ton development office, to work on its efforts. The county would like to attract more high technology firms national and regional headquarters and businesses needing rail connections.

The cover of Loudoun County's development information folder exemplifies that county's approach. It features a drawing of farmland, a hunt scene, Dulles Airport and the tip of the Washington Monument in the distance.

"Dulles is the key to what will happen in Loudoun County in the future," said June M. Bachtell, Loudoun's director of economic development. Bachtell, whose threeperson department was created in 1979 and has a budget of $104,000, says Dulles was a key factor in getting European companies like the German plastics manufacturing firm Rehau and the Danish hi-tech company Skatron to locate in Loudoun.

The type of businesses each jurisdiction seeks depends in large part on the particular city or county's nearness to the District and the availability and cost of land. There is very little interest anywhere in Northern Virginia in heavy industry.

"The situation dictates it," said Alexandria's Montague. "The land costs a certain amount per square foot, and that precludes a lot of types of industrial development.

"Does the client need to be close to National Airport, the Capitol or the Pentagon? And does he still want a river view with the Old Town ambiance?" asked Montague. "(Alexandria is) a self-contained city, not a county, and it's not lost in a big political view. It has tradition and identity."

Montague says that's what brings national associations, research and development firms, companies with government contracts and regional offices to Alexandria.

The type of prospects who sit in the Fairfax office board room and watch the 12-minute film about the county -- complete with shots of Bloomingdale's, the Concorde and the county schools -- are likely to be executive or site selection committee members from such businesses as computer firms, national associations, corporate headquarters, hitech firms and telecommunications companies.

"Business not appropriate to the quality of life in Fairfax County, we tell them we're not interested," said Charles G. Gulledge, chairman of the Fairfax County Economic Development Authority, when asked whether the county works at all with heavy industry."And we send them back to the state so they (state officials) can redirect them to another area of Virginia."

"There are a few places in the county that you could put a steel mill if you wanted to, but I wouldn't anticipate that happening," said Herrity. "Most heavy industry is inappropriate here because the labor force for it just isn't there."

Among businesses that recently moved to Fairfax County are USAir, GCC Beverages (Pepsi Cola distributor) and a Marriott Corporation hotel.

"Arlington has only one major client: Class A office-space seekers," said Parker. "While other areas may have industrial parks or research and development clients, we have very few inquiries about new shopping centers or from industry."

And he says the current economic situation isn't stopping inquiries. "It doesn't appear as though things are slowing down either," said Parker. "There is still a lot of activity and interest."

The volume of calls is heavy in all three offices, representatives say. "We have six phone lines, and sometimes they are all busy," said one staff member at the Fairfax office, which through follow-up studies has traced almost a quarter of the 12,000 inquiries in the last fiscal year to its advertising campaign.

Montague, whose office has no advertising budget, plunged into his job in Alexandria by starting to call all of the national associations located in the District and ask them about relocation plans. "I began by calling 20 associations a week," he said. Now he says he's busy with follow-up work and "I'm lucky if I have time to call five a week now."

The jurisdictions also get referrals from the state Division of Industrial Development. According to a staff member, Fairfax sometimes gets European referrals from the state's office in Brussels.

Recent companies to move to Fairfax as a result of these referrals include a Swedish manufacturer and a German research firm.

Although the jurisdictions compete with each other somewhat for businesses, it's more that Northern Virginia is competing with the rest of the Washington metropolitan area and sometimes the rest of the country.

Fairfax officials say that some companies looking at that county also consider Montgomery County to have a "similar quality of life," and European firms often are looking also at Atlanta, Houston and Dallas-Fort Worth.

"Frederick, Md., is probably the area Loudoun County competes with most often in the area," said Bachtell.

But the jurisdictions also share in each other's successes.

"We are all selling the Washington metropolitan area," said Bachtell.

"If Northern Virginia gets sick, we will share in the illness also," said Dodd of Prince William. "As long as we are healthy, the prosperity of Prince William will reflect to Fairfax, Loudoun and Fauquier and vice versa."

Other development officials aren't put off by Fairfax County's big budget, flashy ads and sophisticated marketing methods.

"What we figure is that Fairfax County's national ads will bring them to Northern Virginia, and then this will bring them to Alexandria to our restaurants and our homes," said Montague.