Cities are lonely. Philadelphia is no exception. Maybe you want to do something about it?

Maybe, alone with the night, passing under silent, blacked-out townhouse windows in certain parts of Center City, aching for companionship, for the illusion of a relationship, for someone to slap on some long black latex gloves and fill the holes in your soul, you discreetly turn some money into a few hours with a beautiful person experienced at keeping the darkness away.

Or maybe you want hard, quick, raw sex. With anything. Underage, overage, male, female, shemale, indoors, outdoors, whatever. Whatever happens to be on the block when you decide to gamble that the figure in the thigh-highs isn't a cop.

Playing the numbers, odds are you won't be arrested.

Police nationwide don't seem especially eager to make arrests unless they absolutely have to. Larry Sherman, chairman of Penn's newborn Department of Criminology, pointed to the Federal Bureau of Investigation's crime statistics: out of the 13.7 million arrests made in the United States in 2001 for criminal offenses, excluding traffic violations, prostitution and commercialized vice constituted 80,000. Sex offenses except for rape and prostitution resulted in 91,000 arrests, while robbery and aggravated assaulted combined totalled 700,000. Drug-related offenses resulted in 1.6 million arrests -- twenty times as many as were made for prostitution which is, according to Sherman, "far more common than robbery or aggravated assault."

Though the sex trade has never achieved the social quasi-legitimacy of, say, legal gambling, its popularity seems rooted in some dark, black-satin-sheets-under-a-ceiling-mirror corner of the human condition.

"There is something about buying these services that persists in attracting a market demand," Sherman says . "With the sexual revolution... everyone expected prostitution to disappear, and then people like Hugh Grant got arrested for illegally using the services of prostitutes and everybody went 'What?'"

Grant could probably have found some companionship without having to pay for it. Hardly a case of a creepy old man with a rash and a beer gut cruising for a good time, Grant's 1995 arrest for soliciting the oral services of "Divine Brown" was a reminder that Johns are as diverse as the prostitutes that serve them.

And whatever kind of john you are, whatever your budget or preferences, Philadelphia's prostitution industry has something for you.

"You've got a pretty good mix in the city," says Lt. Charles Green, commander of the Philly Police Department's Citywide Vice Unit. "In certain areas its more prevalent at the street level... in areas where narcotics are really prevalent - they're out there to make money to buy drugs. In the Center City area, you'll see a lot of the indoor prostitution, where they front themselves as massage parlors and escort services."

Basically, prostitutes tend to stay out of better neighborhoods because, if the local community is strong enough and isn't comfortable having its children propositioned on the way to school, it will get the prostitutes moved.

"Police can make prostitution arrests like shooting fish in a barrel," Sherman says. "In the U.S., the energy that the police spend on prostitution control is proportional to the disruption street solicitation causes. The demand for police intervention when street solicitation becomes obvious and intrusive can become very high."

Sherman notes that "lack of demand can sometimes reflect the sense of powerlessness in areas, like the 10th Avenue area in New York. After prostitution got moved out of Times Square in the '70's, it all ended up there."

Despite this occasional migration, people who want to find the professionals know where to go.

"Every city has its own peculiarities, and people tend to be aware of them," says Ralph Taylor, chairman of Temple University's department of criminal justice. "In Minneapolis, these places advertise as health clubs, and there's one exercise bike out front and a girl in the back. Everybody knows what the garage-converted-to-'health club' is."

Sherman notes that a few decades ago authorities tended to encourage that kind of clustering.

"At one point we... had red light districts in American cities, which weren't legal but were de-facto," he says. "The system... involved massive police corruption, making some police captains millionaires."

Philadelphia has had its share of allegations of police corruption and out and out strangeness as the city government has regulated the sex trade over the years.

The Philly P.D. got an especially large amount of bad press in the independent media over the officers allegedly involved in the case of Mumia Abu-Jamal in 1981, as Jamal's lawyers claim that the officer Jamal was convicted of shooting, Daniel Faulkner, had actually been the victim of a hit coordinated by crooked police protecting a prostitution racket. The 80's also saw dozens of instances of corruption in the Narcotics unit.

More recently, in early 2000, a city-funded program called Prevention Point -- an organization committed to stemming the spread of AIDS, among other things -- released a pamphlet, "Tricks of the Trade," that gave practical advice on maintaining a career as a prostitute.

After Daily News columnist Elmer Smith pointed out that the pamphlet went a little farther than its public health mandate demanded, offering advice on wardrobe and business ranging from the assertion that "clothing and accessories should be attractive to customers, but... do not wear anything that will slow you down if you have to run," to "Have a price list and time limits and stick to them -- get your money up front," the city revisited its decision to bankroll the soon-discontinued publication.

Interestingly, responses to a Daily News poll packaged with the paper's coverage of the story over several days revealed 51 "hot spots" of prostitution in the city, 10 of which were in West Philadelphia.

For the most part, however, Sherman says that authorities nowadays just don't want to get involved.

"Unless there's pressure... I think most big city police departments would prefer to stay out of the business," Sherman says. "The effort's not justified. Police see that public disapproval of prostitution isn't anywhere near public disapproval of robbers. And if you ask people if they'd rather have the police catch robbers or prostitutes, they'll say robbers."

So, at the more expensive end of the prostitution spectrum, the operation is invisible.

"In my former neighborhood in Washington, there's a multimillion dollar mansion that went up for sale on embassy row and is now an embassy," Sherman remembers. "In its previous incarnation it had been a brothel, mirrors on the ceiling... everything. I had walked past it every day for about 3 years and I never had any idea what was going on in that place until it went up for sale."

If a whorehouse operates in the city and nobody hears it, police and residents seem more than willing to leave innocuous looking stones unturned.

"How much harm did it do to the neighborhood?" Sherman asks. "Apparently none if nobody noticed."

His unit doesn't "put our hand in the bowl and say 'we're going to this spot this week,'" Green says.

"We've gotten complaints from spouses who've seen their credit card bills. Anonymous letters, information from community groups. And through our own monitoring of the crime system, we identify these spots. At some of them, robberies are taking place... disturbances, disputes over service."

Green adds that the presence of "scantily clad females" and unusually large stocks of condoms tend to be indicators of prostitution.

And, of course, there's the advertising. Independent operators as well as organized brothels and agencies take out dozens of ads that range from alluringly vague to coldly specific. If you can't be obvious about selling sex on the street, it seems the best thing to do is to be obvious about selling sex in Citypaper.

"We certainly know that in the back of the Citypaper... more than likely they are fronts for prostitution," Green says. "Ninety percent of those locations we've made arrests at."

Green adds that he's noticed that "a lot of the massage parlors are not advertising now."

Nevertheless, advertising for "escort services," "modeling agencies," and women who just come straight out and sell their time by the hour are abundant and explicit, a measure of the prostitutes' confidence that they'll be left more or less alone.

"If there's a flourishing advertisement market, it must mean the risk of attracting an undercover is fairly low," Sherman says.

They still take certain precautions when beginning negotiations with their customers, however.

Calling an agency whose Citypaper classified lists a number of girls, including one hundred-pound nineteen year old "w/ a PhD in Greek," we reached a man who wasn't interested in explaining what services the business provides..

"That is not a question you ask on the phone," he says. "You know what you're calling for."

Well, yes. Greek lessons. Sadly, the opportunity did not present itself to ask what the "X-rated blonde that will swallow you whole" would do during the half-hour $200 would buy.

Isabella's of Philadelphia, a Center City "modeling studio" whose phone number is listed as belonging to a house around 20th and Arch, offers models "professional and skilled in the art of enjoyment," who provide customers "with the most unforgettable GFE," an acronym for "Girlfriend Experience" -- which Isabella's does not define.

What kind of girlfriend experience? Real customers don't ask these questions.

The woman working the phones at Isabella's sends callers to their site. "Since you're a first time caller, check the web site, all I do is make appointments for the models," she says.

On the web site, the agency claims to provide the services of around a dozen women, most of whom who are only available in the city for a week or two at a time. The staff models have short blurbs under their pictures, one of which reads "If you like to see my succulent red lips around you while I look up at you with my green eyes..."

It doesn't take an especially dirty mind to guess what "Gabrielle" means. At the same time, she promises nothing.

"There's certain word games that are played," Green says. "They try to be cute. But a lot of times they're not as educated as they think they are. They use slang or code words and they think that doesn't count."

Some don't even bother.

On The Erotic Review, for example, customers are encouraged to review and compare dozens of escorts and escort services. Claiming that "The bonus is that the opinions expressed are real and not sent in by the adult entertainers themselves," the site boasts that customers can "now know exactly what to expect before you make the call and spend your hard earned money."

The site is visit-to-the-doctor thorough. Customers can search for girls by how their breast appearance ranked (the scale runs from "flat" to "super nice" to "unnatural"), the number and/or location of piercings and tattoos and other details of personal grooming. Overall ranking run from "1 -- I was really scared" to "10 -- Once in a lifetime," and customers can write detailed accounts of the services they received.

Green declined to offer details on police tactics.

"We know that they're out looking for us," he said, noting that "in one spot... they had descriptions of our undercover officers."

Generally, Green said that before an arrest can take place, "the girl or the guy has to offer sex for money."

Further, according to Penn law professor David Rudovsky, undercover officers can refuse to identify themselves during operations, even if asked.

"Simply not responding or denying [that he was a police officer] would not be grounds for an entrapment defense," Rudovsky said. "Entrapment only works if the police conduct is so overreaching that it will lead one who would normally not do something to do it, so it's pretty hard for someone who's engaged in prostitution or selling drugs to claim."

Sherman confirmed that no case law he's seen has indicated that police are obliged to be honest while undercover, leaving the officers relatively free hands.

Undercover, the officer simply has to get the girl to make the offer.

"The undercover's job, you would try to be as specific as possible and have the conversation recorded," Sherman said. "It's the sort of thing that's commonly done by the Drug Enforcement Administration and others -- it's pretty hard to sell somebody a half a million dollars of cocaine if you're not explicit about it. The same thing is fairly easy to do with prostitution."

How much do these arrests mean to the prostitutes? A few hours of lost work time, according to Sherman. Nothing more.

"The transaction cost for getting arrested and being cut loose a few hours later is fairly low," Sherman noted. "It's not as though they're not going to get admitted to law school because they get their 58th prostitution arrest."

Even when a house of prostitution is discovered and busted, the victory is rarely permanent.

"We might close down a spot, but they'll open up under a different name, but the same type of business," Green says. "We've had spots, especially one [on] Sansom Street -- 17 investigations and close to 60 arrests."

Green, who has 20 years of time with Patrol, Narcotics and S.W.A.T. along with his past two years in Vice, says he's going to keep at it.

"We do see a lot of the same people being arrested... but we're in a situation where we have a crowding problem in the prisons," Green said. "I can understand the reasoning. Prostitution is not a violent crime, it's a quality of life issue -- it gets frustrating, but we do the best with the cards we're dealt"