Sometime later this year, if all goes according to her plans, Karen Faulkner Bolle will stand on The Metropolitan Opera stage, making her New York debut as a professional singer.

Until then, Bolle, 33, a former interior designer, will make much of her living from the proceeds of what Fairfax County police say is the largest massage parlor operation in the county and probably one of the largest in the Washington area.

Before her separation last year from Karl, her German-born husband, Karen and Karl Bolle, who once ran a small export-import business in Reston and now lives at Woodley Park Towers in Washington, is still the principal behind two of Washington's largest massage parlors and two "outcall massage" services, according to public records. He would not agree to be interviewed for this story.

Karen Bolle's two massage parlors advertise that they had "5,000 Virginians" as customers last year. Based on her estimate that the typical customer at her "Valentine Health Spas" will spend between $50 and $100 per visit, that means her parlor easily could gross about $400,000 a year.

Multiply that by the 50 massage parlors, plus "outcall massage" and "escort services" that have sprung up in Washington since 1970 and the large financial scale of this sexually-oriented business becomes apparent. Massage parlor owners make "more money than you and I will see in our lifetime," said one lawyer who has represented several of the owners.

According to police and other sources, many of these sexually oriented massage parlors are merely a new form of institutionalized prositution. The most elaborate parlors have a variety of assignation rooms designed for varying sexual tastes. The boldest operations, which refer to themselves as "out-call" massage services, usually supply what amount to call girls to customers in hotels, motels and apartments.

Many massage parlor operators argue that their establishments are quite different from the outcall services. College-students Karen Bolle, who drives a large Mercedes with her initials on the license plate, says further that her parlors, located in Fairfax's Merrifield industrial park and at Bailey's Cross Roads, are really different from most parlors which she called "dingy dungeons."

"There are, as you probably have discovered, two kinds of girls in this business: the hard-core type who have what you call . . . the hooker mentality," she said. And there are "the nice, wholesome type . . . a girl you can talk to." These, she said, are Valentine's girls.

She said that when she discovers a woman with the wrong "mentality" in one her parlors, she fires her immediately. Does that happen often? "Many, many" times, she said. "Every week, we fire people."

At Karen Bolle's "Valentine Health Spa" in the Merrifield Industrial Park, a customer must pass through a series of security doors before reaching an entrance lobby watched over by a closed-circuit television camera.

A hostess - on a recent visit, it was a slender oriental woman in a shoulderless jump suit - emerges from a darkened hallway to quote prices of $70 to $100 an hour for the use of the rooms. The tab can be charged to a Master Charge account, she explains, and the bill will not reveal where the money was spent. It simply will be charged to a general corporate name.

The rooms of the establishment appear to be lavishly decorated bedrooms where the principal - and, in some rooms, the only - furnishings are queen-sized beds. A $70 room was small with a smaller, modernistic bed and an Indian-style rug decoration. Several $100 rooms have stereo radios, dim lights and big beds, one a four-poster with fluffy white crinoline covers. Two rooms have cream-colored, sunken bathtubs and one has a whirlpool bath.

Most of the massage parlors in the District of Columbia are less impressing, such as the Cat's Pajamas, located in a residential neighborhood in the top of a rambling, old frame house on 41st Street NW, and just off Wisconsin Avenue. That establishment, however, provides an illustration of some of the parlors' anbiguous legality.

According to court records, when a man offered a woman attendant at the Cat's Pajamas $40 for sex, she said she didn't discuss such things. Yet, minutes later, she had led the man to a small, upstairs room. In swift order, she pocketed his $40, peeled off her clothes, began rubbing his chest and offer him a condom.

At that point the man announced he was an undercover policeman and placed the woman, Sandra Jean Deinlein, under arrest for violating the District's law against cross-sexual massages. Although Deinlein was convicted her lawyer in an unusual statement, said in court the police would have had a better case had they elected to charge his client with prostitution. The law against cross-sex massages, he argued, was unconstitutionally vague and broad, and he has appealed.

The Deinlein case, one of four now under review by the D.C. Court of Appeals, speaks volumes about his newest twist in the oldest profession. III defined and scanty laws, buttressed by liberal court interpretations, have turned Washington into a refuge for massage parlor operators driven out of other locations.

The Cat's Pajamas illustrates another apparent geographic trend in the sex business - a movement from Baltimore to Washington. Law enforcement authorities say they have identified the parlor's owners as including a Glen Burnie man, 14 of whose Baltimore parlors were closed several months ago under a disorderly house statue.

Baltimore police earlier tried to enforce a cross-sexual massage law similar to the District's but were stopped by parlor owners who obtained a court injunction. Police then invoked the disorderly house law. In Washington, too, massage parlors organized and, with the help of civil libertarians concerned about the extent of police powers, squelched legislative efforts in mid-1976 to strictly regulate massage parlors.

Even the watered-down laws on the books are easily circumvented. A massage parlor that recently moved to Washington from Alexandria was able to skirt an emergency zoning regulation by declaring itself "no sexually oriented."

But the legal attacks, however, inconclusive, have diminished to some extent the city's massage parlor population, from more than 40 in 1976 to 27 today. The surrounding suburbs combined have slighly fewer licensed parlors than the city's total.

A hodge-podge of restrictive zoning laws has limited the locations of new parlors to regional shopping centers in Fairfax County, industrial parks in Prince George's and certain commercial areas in the District, but not affected operations that predate the new codes.

The crackdown, although ineffective and inconsistent from jurisdiction to jurisdiction, also has increased the "out-call" massage business. "And you have to do," said one outcall operator, "is look in the phone book and you can have a rather do that than take his chances at Logan Circle?"

The outcall massage business is widely regarded by its practitioners as a physically riskier if more lucrative livelihood, and by police as a nearly prosecution-proof form of prostitution.

One policeman told of renting a hotel room and calling for an outcall masseuse. The woman arrived, immediately disrobed and sprawled on the bed. "That will be $69," she said. The officer handed it to her and she motioned him to set it on the dresser.

"What are we going to do?" the undercover cop said.

"You're going to get a massage," said the woman cooly.

The officer thought a moment. He could not disrobe, and he needed an overt act by her to make a solicitation case. "Will I need some protection?" he said.

"What for? the woman replied. "You're only to get a massage."

The officer arrested her, anyway, and thought he had a good case because she had undressed and discussed money. The prosecutors wouldn't touch it.

Several such outcall services boast of "radio dispatched" masseuses, women who carry pocket-sized pages with them at all times. "Some of these women run from one room to another in lingerie," said the security chief of a major Washington hotel. "You can hear their beepers go off."

"Our girls are young, attractive and completely uninhibited," promised the man at Tender Loving Care, an M Street SW-outcall operator that accepts credit cards and personal checks.

Some of the massage salons, which now call themselves "entertainment," "encounter" or "health" establishments to skirt zoning laws, offer rooms equipped with waterbeds, pornographic movies, piped-in stereo, a fully stocked bar and nude women. The cost, which may include various forms of sex, can reach $300 for a few hours.

Among massage operators, there is also a hierachy based on how prestigious or seamy the location. "Some of those places along 14th Street are trash," sniffed the owner of one establishment near DuPont Circle. "They have women right off the street, drugs, prostitution, you name it, you can get it there." What goes on in his salon? "Don't dig into my guts too deply," the owner said.

For a parlor massage, the regional range of prices quoted over the telephone runs from $15 to $100 for starters. And the variety of services, according to masseuses, has become increasingly kinky, including "torture rooms" offered by some.

For $75 an hour, a man can be whiped by black-booted women who, according to one police investigator, offer to wide selection of belts" and a padded table, complete with straps.

"If you aren't wild and crazy, you shouldn't be in this business," confided a Maryland woman who recently left her $300-a-week massesue job rather than face increasingly stiff competition from the "really bold" women she says have become more and more the rule in the business.

Increasingly, the business is either attractive or producing unhappy women. The career of one young masseuse ended tragically Nov. 4 in what Alexandria police described as an apparent suicide. "It's bad on your head," said one former masseuse of the business in general.

Many masseuses start out with problems, she said."Working there just messes them up more," said the woman, who sought psychiatric help as a result of her employment.

A high percentage of masseuses are divorced women seeking not money but reassurance that they are sexually attractive, according to Harold Greenwald, a professor of psychology at a San Diego, Calif. university who has completed two studies of prostitutes.

At first, they feel good because they are desired, Greenwald said, but then become depressed by the reality of the job. "That 'happy hooker' is a myth written by some PR man," he said.

The myth is further exploded by another occupational hazard, a consistent undercurrent of violence that seems to plague massage parlor operations. Many of the incidents go unreported to police by parlor owners who fear official harassment and by customers fearful of losing their anonymity.

Some do reach police, however. Between June, 1973 and February, 1974, shortly before police closed Arlington's 11 massage parlors, law enforcement logbooks there recorded 11 prostitution arrests, three petit larcenies, four armed robberies, two rapes, one homicide, one burglary, two assaults and assorted other crimes at the establishments.

For those in the business, however, the benefits often seem to outweigh the risks. Women responding to newspaper want ads are promised easy earnings of $100 per night or $600 per week, "more, depending on what you do."

Virtually all masseuses receive commissions rather than salaries, often earning as high as 50 per cent of the take for "manager-masseuses" and rarely less than 30 per cent. "You can make as much as you want to put into it," said a masseuse-turned-hairstylist.

For the owners, there is generally low capital investment and overhead and high profits. One cost that differs from place to place is the licensing fee. It ranges from $300 in the District to $1,500 in Prince George's County, $2,000 in Fairfax and $5,000 in Falls Church.

Willingness to pay the high fee is testimony to the profitability of the business. "One woman came in and wrote a check for $1,500 like you or I would write one for $5," said an astonished John D. Wildman, of the Prince George's business license office.

Customers run the gamut, according to masseusers. Some just want someone to talk to. Others want plain sex. Still others have special psychological needs.

Most owners try to keep strong tabs on their employees through lie-detector tests, one-way mirrors and "codes of ethics" - often for later use in court - in which the women agree not to engage in sex on the job.

"You should make certain that all customers leave happy but without any involvement of sex," read one code issued by an Arlington parlor.

Another parlor required women to sign a statement that they did not work for the local government or a newspaper and agreeing to lie detector tests "without notice."

Such tests often are used by parlor owners to ferret out police informants and to keep track of masseuse earnings. Another practice, known as "running you," involves owners' agents posing as customers to learn how much the women are charging.

Masseuses must be specially licensed in nearby Maryland and Northern Virginia suburbs but not in the District. In Prince George's County, a requirement that masseuses receive 500 hours of training was hotly but unsuccessfully contested by parlor owners. Consequently, the county's massage parlor files are stuffed with certificates from the Anderson School of Scientific Massage, Princeton Ill., and the School for Medical Gymnastics & Massage at the Swedish Institute, New York City.

Who owns the parlors? In suburban Maryland, it's a matter of public record, as it is in Alexandria. Fairfax County Cpl. J. A. Thomas, who handles parlors and taxi permits, said the parlor permits are protected by the state's privacy act.

District ownership also is difficult to pin down. There is no law regulating parlors or requiring disclosure, and the names often appearing on occupancy permits are merely corporate agents or employees, "accommodation officers" used to meet legal requirements that someone be responsible.

In a blunt letter to Alexandria officials, Howard M. Rosenberg, a Washington liquor wholesaler, said he waned his ownership of "The Wolf's Den," listed in the name of JFI Inc. to avoid "harassing phone calls."

When The Wolf's Den moved to downtown Washington recently, the occupancy permit contained other names and the name of a corporation of which Rosenberg is president. "If my name is used," he subsequently told a reporter, "I'll hold you and The Washington Post responsible . . . You're looking for garbage."

Other operators acknowledge their interest and strongly profess innocent intent and obeisance to all laws. "It's a massage parlor, not a brothel," said one Prince George's parlor operator. "They (the employees) have been instructed that they will be fired for any such (prostitution) action."

However, discussing employees' skimpy attire, he told county officials at an informal hearing, "We try to skirt the law."

Whatever the law allows or doesn't allow, massage parlors have established a definite image as part of the multi million dollar sex industry. That image in turn, has created serious problems for the respected profession of physical therapy.

Slim-Form, a Mount Rainier salon in business since 1966, whose customers are men and women over 40 years old, does not advertise in the newspaper, owner Ellen V. Mitchell told cunty officials, because "We don't want that kind of clientele."

In Montgomery County, Jeanne Albano, a masseuse with training in acupressure, electrotherapy and reflexology, said she often gets telephone inquiries from men who want to know what she wears.

"I teel them I'm in full uniform and that I've been doing this work for 25 years," she said, wearily. "They usually hang up when they heart that."

Also contributing to this story were Washington Post Staff Writers Jane Seaberry and Ron Shaffer.

Next: Adult bookstores in Suburbia.