By TIM WEINER

TIJUANA, Mexico — Millions of Americans come here looking for trouble. They usually find it. Alfredo Anzaldúa's occupation is to get them out.

Mr. Anzaldúa ("Call me Al") is the American citizens services officer at the United States Consulate here in Tijuana. The job has made him a connoisseur of human
folly. The deacon in the drunk tank, the rich kid run amok, the cop with a badge of gold and a heart of tin are his stock in trade.

Thousands of Americans young and old come every day and every night to Tijuana, across the busiest border in the world, with one goal in mind. They want to get
lost.

"They come here to do things they would never think of doing in the United States," Mr. Anzaldúa said. "They get blind drunk. They buy drugs. Then they try to buy
their way out of trouble. This gets back to the image of Tijuana I heard about growing up."

Tijuana became a mecca for American miscreants during Prohibition. Within sight of the border stood hundreds of establishments offering forbidden fruits: sex, drink,
drugs, gambling, the whole gilded palace of sin. All of these and more are still on sale, making the city "a Disneyland for adults," as Mr. Anzaldúa put it.

The drinking age is 18. Prostitution is legal and closely policed in a certain part of town, the Zona Roja, or Red Zone. American men of all ages haunt the Zone. Some live and die in its $10-a-night hotels.

All along the main drag of Tijuana, Avenida Revolución, the bars spill out into the streets. Some admit underaged girls, Mexican and American, as bait to attract men. Bad things happen in some of these bars at 2 a.m., says Mr. Anzaldúa. The next day, an hysterical parent is on the phone from some southern California suburb, screaming, "Where's my daughter?"

There may be no answer. Sometimes the answer is unbearable.

"People disappear," Mr. Anzaldúa said. "Usually three a week. And sometimes they never appear again."

On Revolución and its side streets, shills and barkers and touts whisper, "Whaddya looking for?" They offer cures for whatever ails. American bodybuilders and
amateur athletes have created a booming illicit market in anabolic steroids. The Zona Roja aficionados buy Viagra by the fistful.

Pharmacies offer prescription pain pills under the counter. Some deliberately sell illegal amounts of legal drugs to bargain-hunting Americans, in a classic Tijuana
extortion scheme described by Mr. Anzaldúa:

"A shill pulls the citizen in," he said. "The pharmacy sells the citizen lots of medication — illegal amounts. Next thing, a couple of cops approach. `Do you know this is illegal?' say the cops. `You could go to jail for this.' Which is true."

Their embarrassment creates a golden opportunity for extortion; the police then take the Americans from A.T.M. to A.T.M., extracting a large on-the-spot fine.

There are worse places on earth to be imprisoned. But not very many, especially for "respectable people with respectable lives in San Diego" and "rich kids from nice families whose parents would flip if they found out they were sitting in a Tijuana jail," said Mr. Anzaldúa.

This is a sad story, often told. But a new twist lies ahead.

Tijuana's leaders are tired of serving as America's Sodom. San Diego's city fathers are weary of bailing out their children. In late March, the mayors of the two cities
teamed up with Tijuana's chief municipal judge, Juanita Rojas, its international relations chief, Paola Navarro, and the American Consulate to attack the root of this
problem.

Realizing they cannot change human nature, they are trying to teach Americans that there are laws here. They have produced an extraordinary little pamphlet that
appears to have no precedent in the annals of Mexico.

The pamphlet, called "Know Your Rights in Tijuana," can be read online (www.tijuana.gob.mx/Turismo/TouristGuide/English/index.asp). Among its many useful facts is a list of the top 10 crimes committed by Americans in Tijuana. They include:

Appearing naked in public.
Satisfying physiological needs on the street.
Disturbing the peace while intoxicated.

Disobeying a legitimate order given by a public authority.

This last offense needs explanation, which the guide, surprisingly, gives. It dares to ask the question, "What should I do if a police officer asks for money?" Moreover, it dares to answer it.

"You should always politely insist on a written citation," it says. "Offering money to a police officer to avoid a ticket or other penalty is a crime in Mexico. Likewise, it
is against the law for a police officer to demand or ask for money."

The pamphlet lists the 24-hour number for the city's office of internal affairs, which is intended for American and Mexican citizens to report extortion by police and
officials. It even provides a simple form to submit. And it offers some sound counsel. "Use common sense," it advises, "and respect the law."

In the unlikely event that this wisdom prevails among Americans in Tijuana, Mr. Anzaldúa, 56, might no longer be the world's busiest consular services officer. He
could be reduced to helping rescue stray backpackers and AWOL servicemen.

He has had odder jobs, having sold shoes, taught English in the United Arab Emirates, worked as a halfway-house counselor and served as a president of the Tucson Space Society. He joined the State Department only 10 years ago, after his wife advised him to "find a job where they pay you to move around." As a vice consul in Ecuador, he once was offered a parrot as a bribe. He came to Tijuana two years ago and never looked back

Today, he says, he holds "the most interesting job in the world." But if Tijuana ceases to be Sin City, Mr. Anzaldúa will have to find new work.