Wild and wicked. Boisterous and bawdy. That was San Francisco long ago.

There were high-class parlor houses and low-class brothels, high-class gambling establishments and low-class bookie joints. There were good gangsters and bad bandits. There were prostitutes who married into San Francisco society and one who became mayor of Sausalito.A lot of San Francisco's storied history is still evident - in spirit, for sure, and even in some sites.

Its salacious skeletons all come out of the closet thanks to Mark Gordon, an articulate author and trivia whiz who leads several off-the-wall tours of the city.

One of them is the Great Frisco Crime Tour, an interesting and entertaining two-hour walking trek through San Francisco's rollicking and raucous past, from Gold Rush days through the 1920s, '30s and '40s. Gordon dresses the part in pin-striped jacket and fedora, recapping some of the city's crimes and retracing the steps of several of San Francisco's greatest characters. He gives special insight into one of America's most beloved cities that you won't get on a Gray Line bus tour. And you don't even visit Fisherman's Wharf.

Gordon's crime tour departs from the Westin St. Francis Hotel, itself the scene of numerous notable happenings. It's where 64-year-old entertainer Al Jolson died in 1950 during a card game in a penthouse suite. He went very quickly, Gordon recounts.

"He said, 'Fellows, I'm not feeling well.' He went back into his bedroom and in a couple minutes he just died."

The well-wired San Francisco Examiner sent a reporter and photographer to the hotel immediately. The photographer, the story goes, rearranged the cards at the table and gave Jolson a pair of aces and eights - Deadman's Hand - the same hand Wild Bill Hickok had when he was shot in the back in Deadwood, S.D. - and the report that Jolson died with a Deadman's Hand settled into the county's lore.

Starlet Virginia Rappe died at the St. Francis in 1921. Silent film comedian Fatty Arbuckle was accused of murdering the woman.

For eight years, Arbuckle went through three trials before being found innocent of the charges. But the publicity had ruined his career. He died a year later.

The St. Francis also is where Sarah Jane Moore attempted to assassinate President Gerald Ford in September 1975 as he was coming out of the hotel's English Grill. A former Marine knocked the gun out of Ms. Moore's hand as she stood across the street about 40 feet away. The supposed bullet hole is visible next to one of the hotel awnings.

The venerable hotel borders bustling Union Square, which gets its name from the Civil War era, when it was the site of pro-Union demonstrations. (This particular weekend there are anti-fur demonstrations.)

Nearby, Maiden Lane originally was called Morton's Alley. It was the heart of the low-cost brothel district, with about 60 of the worst type of brothels in San Francisco, Gordon relates. "They were called cribs. There were literally hundreds of rooms, about 6-1/2 feet by 4-3/4 feet, in each of these buildings.

"And it was just one very quick turnover after another, the McDonald's of San Francisco prostitution history. Literally, 80 to 100 men a night would frequent a number of the more popular prostitutes."

Which brings up another character in San Francisco's history - Sally Stanford, probably one of the most famous madams in the United States.

Despite 17 arrests and four convictions as a madam, Ms. Stanford was elected mayor of Sausalito in 1976. She died in 1982.

Another high-class lady of the night was Maude Nelson, who worked out of a parlor at what would have been 404 Stockton St. She married Charlie Fair, son of high-society's James Fair of Fairmont Hotel fame, a silver baron who was wildly opposed to the marriage.

Enter again William Randolph Hearst, who conspired with James Fair and came up with a plot. They knew the newlyweds were going on a honeymoon in Nevada and that they had to change trains in Vallejo.

Hearst arranged to have Charlie Fair arrested when they changed trains and taken to a Napa hospital. He would be arrested on grounds of insanity, because, if he weren't insane, how could he have married that woman? Hearst went ahead with the story the next day, saying Fair was arrested for insanity and his marriage to Nelson nullified.

Unbeknown to Hearst and the father, the couple had taken an earlier train and the plot fell through.

On the outskirts of Chinatown, Gordon leads the group up steps above the Stockton Street tunnel.

"Imagine, if you can," he says, "it's 2 o'clock in the morning on a weekday night and you're walking up these stairs alone on a very dark, misty night."

We are standing in Burritt Alley. This is Sam Spade, or Dashiell Hammett, territory. It's where the movie "Maltese Falcon" supposedly took place.

A plaque on a building honors the fictitious spot where Miles Archer, fictitious partner of the fictitious Sam Spade, was "done in by Brigid O'Shaughnessy." At the beginning of the movie, Archer gets shot and killed halfway down the alley. It looks like Burritt Alley, but the scene actually was shot in Hollywood.

The movie, starring Humphrey Bogart as Spade, became a classic and earned an Oscar for director John Huston.

A block away, Dashiell Hammett Alley, which used to be Monroe Street, was one of eight or 10 places where the pulp writer lived. Suffering from tuberculosis that he contracted in World War I, he came to San Francisco in 1921 and, like everyone, fell in love with the place. He wrote almost all of his five novels here, and literally wrote "Maltese Falcon" in a couple of days in 1930.

He later moved to Los Angeles and wrote "The Thin Man" series, which was based on his relationship with playwright Lillian Hellman.

One of San Francisco's craziest stories involves Black Bart, whose real name was C.E. Boles. The West's most successful lone stagecoach robber, Black Bart started his questionable career around 1878 while in his 40s. Perhaps it was a mid-life crisis.

He lived a quiet life most of the year in the 300 block of Bush Street as retired miner Boles. But three or four times a year he ventured out into Gold Rush country north and east of San Francisco and robbed Wells Fargo & Co. stagecoaches. "He only robbed when he needed to," Gordon says.

He never harmed anyone and he never loaded his shotgun. He garnered a Robin Hood reputation because he didn't take valuables from passengers. "I only rob Wells Fargo. I don't rob from the common folk," he told at-first frightened riders.

On about his fourth robbery, he started leaving poetry and signed it PO 8, for po-eight or poet.

"He didn't use a horse. He actually walked to and from the robberies," Gordon relates. "He would take a train out to the Gold Country and then walk to and from places. He would stop either behind a boulder or up and down a grade where the stagecoach had to really go slowly. It worked 28 straight times over a period of eight years."

On the 29th time, he ran into trouble. He left a handkerchief at the scene of the crime. Wells Fargo detectives traced the laundry mark to Black Bart's neighborhood and the laundry owner looked up the marking. "Yes, that's Charles Bowles. I know him well," he told a detective.

Black Bart unexpectedly came strolling around the corner just then, so the laundry owner motioned him into the laundry. Black Bart was introduced to the man who said he had some questions about mining, and asked Bart if he would come with him to his office. Sure. It turned out to be the Wells Fargo building at 420 Montgomery St.

If you want to know what happened from there, you'll have to take Mark Gordon's tour.

IF YOU GO: The Great Frisco Crime Tour is one of five one-of-a-kind tours offered by Mark Gordon and his Frisco Productions.

Two are walking tours - the crime tour and a historic bar crawl tour. The others are bus tours: another crime tour, a Hollywood tour featuring places around San Francisco where movies were shot (including all-time Hitchcock great "Vertigo"), and Sentimental Journey, highlighting San Francisco in the 1930s and 40s.

- Cost: The Great Frisco Crime Tour costs $15 for the two-plus hour tour. There are no big hills to climb, but dress comfortably. For large groups, costumed actors may appear from time to time throughout the tour.

- Reservations: Reservations are essential for all tours. Call Gordon at (415) 681-5555.

Other unique San Francisco tours include:

- The Strolling Nosh. A walking/eating historical tour during which participants sample goodies, such as seafood cocktail on Fisherman's Wharf and sourdough bread in North Beach. Elaine Robinson, (415) 441-4221.

- Art Focus. A walking tour to small, off-beat galleries. Lydia Titcomb, (415) 921-4111.

- Mural Walks. A walking tour of an eight-block area in the Mission District led by the non-profit Precita Eyes Mural Center. The tour covers 40 of 80 murals that decorate many of the building exteriors in the largely Hispanic community. Precita Eyes Mural Center, 348 Precita Ave., (415) 285-2287.

A.M. Walks. Author John McCarroll leads two-hour, early-morning tours (7 and 9:30 a.m.) while the city is still quiet and traffic-free. Highlights include Union Square, Chinatown (including a visit to a fortune cookie factory), the historic Gold Rush district, the oldest buildings in San Francisco (Jackson Square and Barbary Coast areas), and the place where Mark Twain met Tom Sawyer. John McCarroll, (415) 928-5965.

Chinatown Walking Tours With the Wok Wiz. Cooking expert Shirley Fong-Torres, a television chef and cookbook author, leads three-and-a-half-hour tour that includes unusual businesses in alleys, brush painting demonstrations, a private tea ceremony and a visit to a Chinese rice noodle factory. Tour concludes with lunch at a Chinese restaurant. Shirley Fong-Torres, (415) 355-9657.

Information: For more information on other tours and on San Francisco, contact the Convention & Visitors Bureau, (415) 974-6900.