Finally, Campbell stepped off the curb into the path of an approaching truck. "We're safe here," he said as the truck came to a gentle stop. "It's one of our trucks."

The truck is owned and operated by the Jehovah's Witnesses, the religious sect formally known as the Watchtower Bible and Tract Society. Campbell is one of about 3,000 Jehovah's Witnesses who live and work at the sect's worldwide headquarters in downtown Brooklyn.

"All our drivers are obedient to the law," Campbell said. "In fact, all Jehovah's Witnesses are expected to abide by the law. There was no question he would stop."

In New York City, America's capital of hedonism, the Jehovah's Witnesses stand out like prudish parents at a toga party. They are the modestly dressed, clean-cut, sober folks in a city that celebrates the outlandish. They are the courteous drivers on a highway full of maniacs.

The world's 3.8 million Jehovah's Witnesses are perhaps best known for their aggressive proselytizing, their half-dozen predictions about the end of the world, their ban on blood transfusions and their refusal to declare allegiance to flags or governments.

But in Brooklyn Heights, where the Watchtower Society has maintained its headquarters since 1909, they're known for something else: real estate.

"They've become almost a juggernaut of acquisition in the last 10 years because of their tremendous wealth," said Bob Tramonte, the owner of Cousin Arthur's Book Shop in the historic neighborhood overlooking Lower Manhattan.

The Jehovah's Witnesses' land purchases are a continuing source of resentment in the pricey Brooklyn Heights area, where younger upscale and older middle-class residents live side by side. The sect owns about 35 properties, including four of the area's five hotels, and a growing number of brownstones in the quarter-mile by half-mile neighborhood. Sect officials say they need the properties to house the volunteers who work at the headquarters, which they call Brooklyn Bethel.

The uneasy yet genteel co-existence between the Witnesses and the neighborhood came to the fore two years ago when the Watchtower Society sought zoning changes to build a 35-story residence just outside the Brooklyn Heights Historic District. Preservationists and other residents objected that the building was inappropriate and would block the view of the Brooklyn Bridge.

The zoning proposal was defeated, but the fight left a bad aftertaste that continues to sour the relationship on a number of neighborhood issues. Taxes - the Witnesses don't pay any - is one; their minimal participation in the community, or its economy, is another.

"The issues have little to do with them as individuals," said Deirdre A. Carson, an officer in the Brooklyn Heights Association. "It has to do with what happens to any small community when it is overwhelmed by an institution."

But the Witnesses say they are victims of religious prejudice. "We're no threat to their secular objectives," said Robert Johnson, a Watchtower Society spokesman. "But they feel threatened by our religious objectives."

The religious objectives of Jehovah's Witnesses are straightforward - nothing else matters in life but spreading the word of the Second Coming of Jesus, whose Messianic kingdom, they say, could arrive any day.

"That's why we're so aggressive," Johnson said. "The clock's ticking."

To spread the word, the Watchtower Society continues to expand its modern Brooklyn office and publishing complex, which last year printed almost 36 million Bibles, books and brochures. The sect's magazines, Watchtower and Awake!, are printed at a newer plant in Wallkill, N.Y. The magazines publish 25.8 million copies in 108 languages every two weeks.

But Brooklyn Bethel is more than an industrial complex. It is an insular, self-sustaining colony in the midst of Sin City.

Each morning, thousands of Witnesses file out of their residence halls and walk in groups to office buildings and factories, all painted tan. The properties are fastidiously tidy inside and out. The factory workers take showers before lunch.

Even though the Jehovah's Witnesses buy their presses, paper and some machines from outside sources, they manufacture much of their own equipment and materials - such as book-binding adhesive and inks.

They have no aversion to technological innovations. A closed-circuit television system delivers the daily Bible lesson to dining rooms. They have developed a computerized typesetting system that can print in 200 languages. They have manufactured 27 million cassettes of Bible lessons.

The Watchtower Society pays its Brooklyn workers $80 a month to buy personal items, and provides for most of their needs. Their meals are served in the residence halls. Most of the food is grown on Watchtower Farms in Wallkill, N.Y., where 1,000 more Witnesses work, or at a Florida citrus grove owned by a Jehovah's Witness. The food is transported in the Watchtower truck fleet.

The "Bethel family" includes barbers, dentists, doctors, housekeepers, groundskeepers and carpenters. They build their own furniture and make their own detergent. The complex includes shops for repairing personal appliances, watches, shoes and clothing - members pay only the cost of materials.

Although hundreds of workers are constantly shuttling between residences with laundry and food, little of the activity is visible to the public. Many of the buildings are connected by an underground network of tunnels. "We worked real hard to keep the streets looking like a residential neighborhood," Johnson said. "What other institution does that?"

The Witnesses' self-sufficiency irks some Brooklyn Heights neighbors.

"The Jehovahs are not part of the gross national product," said Tramonte, whose bookstore specializes in children's publications. He said the Witnesses seldom buy books - and then, only Aesop's fables or Dr. Seuss books.

But Johnson said the economic complaint is a "lame argument." He said thousands of Jehovah's Witnesses who visit the Brooklyn facility eat in the neighborhood's restaurants and shop in its stores. Even so, he said, "We don't feel any obligation to support any businesses."

Johnson said providing in-house services saves the Watchtower Society's money. That's also why there are few families with children working at the Brooklyn facility. Most of the workers are young adults. If they get married and start families, the Witnesses encourage them to leave and establish themselves in the secular world.

Not all the Bethel residents are young. Frederick W. Franz Jr., the 97-year-old president of the Watchtower Society, lives in the facility's infirmary, Johnson said.

Franz is only the fourth leader of the sect, which was founded in Pittsburgh in the early 1870s by Charles Taze Russell.

Russell, a street preacher, was among several 19th-century advocates of the second Advent, or the Second Coming, of Christ. On Good Friday, 1878, he gathered his followers on the Sixth Street Bridge in Pittsburgh to await the end of the world and their ascendance into heaven. It was the first of several such miscalculations that sect officials today say are embarrassing.

Nevertheless, the sect, then known as the Russellites, grew. It moved to Brooklyn to be close to shipping facilities, and in 1931 adopted the name Jehovah's Witnesses.

According to the Witnesses' interpretation of the Bible, only 144,000 believers will be admitted to heaven and all other believers will live in eternal paradise on Earth.

Their theology, which they are known for carrying door to door, is rejected by mainstream Christian organizations because it departs from the belief in the Trinity; the Witnesses believe that only God - Jehovah - is divine.

And they accept only a government of God. They do not vote, they do not participate in political discussions and they refuse to join the military. But they obey laws as long as they do not conflict with their interpretation of the Bible.

Smoking is banned, some drinking is permitted, but drunkenness is a sin and ground for banishment from the Brooklyn facility. Sexual relations outside of marriage are strictly forbidden. Johnson said that about 40,000 Witnesses were "disfellowshipped" - excommunicated - last year for sexual indiscretions.

All members are ministers - congregations are overseen by elders - and each member must attend at least five hours of services and Bible studies a week. "You've got to be active and aggressive to be a Witness," Johnson said.

Part of that aggressiveness is expanding the sect's real-estate holdings.

"The Witnesses like good real estate," said Carson, the Brooklyn Heights Association officer. "They have a lot of options available to them to buy properties in other parts of Brooklyn, but they want to be in our community because it's pretty."

But the Jehovah's Witnesses argue that Brooklyn Heights is their community, too.