The planned community of Reston is finally getting its downtown, a quarter of a century after the first houses were built in the wooded countryside 18 miles west of Washington.

Reston's "town center" was part of the original plan of the town's creator, Robert E. Simon, but is just now nearing completion.

Several past attempts to get the project underway collapsed, largely because there weren't enough people living nearby to shop in the stores, eat in the restaurants and work in the offices, said Kenneth P. Wong, senior development manager for the town center project.

"The idea of a downtown in the suburbs was something that no one really had a grip on," he said. "It's a very complicated proposition" that needed "a long {research and development} gestation period."

Now, opening ceremonies for the center's first phase are planned for October. By that time, the developers expect to complete work on 550,000 square feet of office space, a 515-room Hyatt Regency hotel, 250,000 square feet of stores, restaurants and movie theaters, as well as 600 apartments. Within about a year, a cultural center with space for galleries and museums will be finished.

Over the years, the town center "has been like the Emerald City of Oz, off in the future somewhere," said Thomas Burgess, executive vice president of the Reston Association, representing Reston's 19,000 households.

He said he was impressed with the project, which fulfills the developers' past assurances that it would not be "another regional mall."

Nearly 40 percent of the office space has been leased, a good deal less than the developers hope to have under contract by opening day, Wong said.

Northern Virginia's oversupply of office space, the slowdown in commercial leasing and cutbacks in federal spending have affected all commercial developments, including the town center project.

"We're as concerned as everyone else about the reduction in {federal} government spending" that has helped dampen the local economy, said Kenneth Himmel, managing partner of Himmel/MKDG Co. of Boston and Chicago.

The town center is being developed by Himmel's group and Mobil Land Corp. Himmel expects that the Washington area market "will continue to be relatively healthy" and that Reston's town center will fare well because it is "unlike anything in this market."

In an aggressive advertising campaign, the developers have run full-page newspaper advertisements touting the project as superior to upscale retail and office neighborhoods elsewhere in the Washington area, saying it will be "Downtown without the high rents, Old Town without the parking problems, Georgetown without the traffic."

Reston already has about 12 million square feet of office space, not including the town center, making it second only to Tysons Corner in the amount of space in any Northern Virginia community, said Wong.

He said the vacancy rate in existing Reston buildings is at about the same level as the rest of Fairfax county's offices, which is nearly 20 percent.

The town center's developers expect to eventually fill their buildings from the "huge base of business activity" in the area around Reston, Wong said.

"So long as the economy is growing modestly and there is continued in-migration" of people and companies, there will be tenants for the town center, he said.

Annual office rents in Reston range from $27 to $30 a square foot, "at the top of the Virginia market and between downtown and the typical low-rise, suburban" development, Wong said.

Like other developers competing for tenants in a soft market, the town center owners offer prospective occupants a "menu of concessions" equal to about 20 percent of the value of the lease, he added.

The first tenants are Rolls Royce Inc. and Molson Breweries USA Inc., the U.S. subsidiary of the big Canadian brewer, each with leases for more than 20,000 square feet in the first of two 11-story office buildings. Two leases for more than 15,000 square feet each have been negotiated with other companies but not yet signed, Wong said.

Three-quarters of the retail space is rented to specialty shops and clothing stores, including Ann Taylor, Banana Republic and Talbots and restaurants such as Clyde's of Georgetown and the American Cafe, and an 11-screen movie theater.

The streets of the development will be lined with $420,000 worth of full-grown trees that will be planted before the fall, and the office buildings surround a central courtyard with a large fountain.

Simon, the New York businessman who developed much of Reston, called the town center project "very exciting" and said it is "to a large extent" faithful to his original plan for the center.

Simon lost Reston to his financial backer, Gulf-Reston, after he encountered financial problems in the early 1970s, and now lives in St. James, N.Y., where he is "semiretired."

Mobil Land acquired the Reston development company from Gulf several years later, and critics say that the two companies have departed from the original concept for the town.

The early leaders of Reston "had a lot of utopian visions of mixed income, mixed races, the socialist new man in America," but that the town now is virtually "indistinguishable" from similar communities ringing major cities, said Joel Garreau, a Washington Post reporter on leave while writing a book, "Edge City," on such urban areas throughout the United States.

"You have to drive to get {to Reston}. You can't walk anywhere in Reston," he said. "It's got marginally improved traffic patterns internally and more density than a lot of places."

But James Cleveland, president of Mobil Land Development Corp. and of Reston Land Corp., said the town center project has turned out "exactly the way it was planned.

"We wanted an integrated, real-people place that you could come to and have the experience of the classic downtown," Cleveland said.

The buildings now being completed along Reston Parkway in the first phase of the project will occupy 20 of the total 460 acres the completed town center is planned to cover.

About 475 condominiums and rental apartments will occupy several buildings to be erected in the next phase of the project, scheduled to get underway next year, said William E. Steiner, Reston Land Corp.'s vice president for residential marketing.

About 145 condominiums will be built in a high-rise building of 10 or 11 stories. Smaller buildings will contain the other condos and rental units.

Steiner said rents will be in the "$1,000-a-month range," but that it is too early to set prices for the condominiums.

Eventually, the town center will contain more than 1,400 rental apartments and condos, Steiner said.

Plenty of Northern Virginia residents will be able to afford them. Fairfax County is one of the most affluent jurisdictions in the nation, with a median income of about $58,537. At $60,395, Reston's median tops the county's.

By the time the town center development is finished, nearly two decades from now, it is expected to contain from 5.7 million to 7.1 million square feet of office space, as much as 450,000 square feet of retail space and more convention facilities in the hotel.