In 1927, when Rudolph Fisher returned to Harlem after five years in medical school, he could still hear the blues at night. In fact, the old neighborhood was ringing with music, dance, and theater. But something had changed. Limousines and taxis lined up for blocks under the glittering entrances to the famous clubs. Subway tunnels swallowed and spit out crowds of party-goers all night long. And when Fisher descended the narrow stairs to one of his favorite haunts, he realized the complexion of the scene was different: "I became aware that, except for the waiters and members of the orchestra, I was the only Negro in the place."

In just half a decade, Harlem's throbbing nightlife had become a magnet for thrill seekers from way beyond the black community. "The Negro is in the ascendancy," said Carl Van Vechten, a white devotee of black culture. "Everybody is trying to dance the Charleston or to sing spirituals." The fact remained that in much of the country, segregation kept whites and blacks apart. But after dark, when the music began to play, the whole world seemed to cross the color line at 110th Street. There, said one black writer, they found a place they thought was "exotic, colorful, and sensuous; a place of laughing, singing, and dancing; a place where life wakes up at night."

HARLEM ON BROADWAY

So what was this funky place all about? Why did people come from miles around to have a taste of Harlem's nightlife? Put on your Saturday night finest, and let's go find out. If you're new to Harlem, you might consider sticking Night Life: Vanity Fair's Intimate Guide to New York After Dark in your pocket. In the chapter on Harlem it warns, "Above all, remember this: Harlem starts strutting late. Before 11 it has scarcely opened. Don't try it till midnight or after."

But who wants to hang out till midnight with nothing to do? So why not start downtown, with the theater? It is, after all, the black musicals that woke the world up to what Harlem had to offer.

If it's 1927, the show to see is Porgy. The cast is almost all black. But if you are too, as you enter the Guild Theater on Broadway, you'll be steered upstairs to the highest rows because the Guild is segregated.

The love story, about a handicapped beggar named Porgy and his girlfriend, Bess, is tragic. The music is beautiful — soaring spirituals sung with blinding passion and the high-stepping music of the Jenkins Orphanage Bank. Critics loved it. Some whites thought they saw in the cast a natural expressiveness that their own race simply didn't have. Blacks generally loved Porgy too, but pointed out that black performers rarely won praise for serious drama. "I wonder," wrote poet Countee Cullen, "if we just naturally must sing all the time."

But tonight we're not out to be serious. It's song and dance we're after, and by the time Porgy lets out, it's 11:00. Not quite midnight, but time to hop a taxi anyway and head north on Lenox Avenue into Harlem.

First stop, the Savoy Ballroom. They call it the Track, short for fast track, because you can find everybody whose anybody there on a Saturday night, stomping away to the best jazz. In fact, people will tell you this is where the world was introduced to jazz. Tonight you're lucky: the band is Fletcher Henderson's, with Coleman Hawkins on sax and Louis Armstrong on cornet.

STOMPIN'AT THE SAVOY

Inside the lobby, both black and white are milling around. A couple of black men with straightened hair, tails, and cutaway coats stand under a huge cut-glass chandelier. On the marble staircase some women in gleaming dresses and fur coats are talking away. Not everyone is rich, though; there are dockworkers and shoe shiners with patches on their pants and holes in their shoes. But once you get on the dance floor, it doesn't matter how you dress as long as you can step. The floor is as long as a football field and about half as wide, all painted in orange and blue. The music is jumping — sounds like "Sugar Foot Stomp" — and it seems like all 4,000 people are out there shuffling and shaking.

Just a block away, the Cotton Club (the so-called "hangout for the mink set") is jumping. Outside, in a neon glow, a crowd of black Harlemites hovers. They're not waiting to get in; the Cotton Club is for whites only, and unless you're performing, waiting tables, light enough to "pass" for white, or very important, Big Frenchy Demange won't let you through the door. Even W.C. Handy, the father of the blues, was turned away while his music was blaring away inside. But while the limousines pull up, Harlemites crane their necks and pick out the celebrities.

Inside, Duke Ellington's orchestra is just ending a set of its silky brand of jazz. The stage is lined with cotton bushes and a rickety plantation cabin, all meant to resemble, says Ellington's son, "not the South of the aristocrats but the South of the Negro." The floor shows are full of light-skinned black women, advertised as "the cream of sepia talent, the greatest array of Creole stars, supported by a chorus of bronze beauties." The act is raucous, with bare legs kicking high to the sound of pulsating horns. According to Lena Horne, who sang at the club in the 1930s, the shows "had a primitive naked quality that was supposed to make a civilized audience lose its inhibitions." Tonight, Bill "Bojangles" Robinson, who can tap dance anyone off the stage, clatters his way up and down a staircase to a thunder of applause.

Once a month or so you might catch a glimpse of the club's owner. He's the renowned, and feared, Owney Madden, a white man with sleek black hair and bullet scars all over his body. Madden made his millions selling bootleg liquor to the throngs who flock to Harlem to drink on the sly. It is the time of Prohibition, and drinking is against the law, but that hardly stops anyone. According to pianist Willie "The Lion" Smith, in one nightclub "you could see a cop almost any night partaking of a juicy steak and a glass of hooch on the house."

Meanwhile, the Cotton Club's lily-white, fur-coated crowd is getting on your nerves. The entertainment is great, but these shows are packaged and performed for rich white folk. There's a more authentic Harlem to be found in the throbbing "rent parties" held Saturday nights in the dark hallways of four-story walk-ups. There you get music, food, and refreshments for a quarter to a dollar — money that goes to help pay the host's rent. You can find invitations everywhere. Yours reads: "If sweet mama is running wild, and you're looking for a Do-right child, just come around and linger." Okay.

At 130th Street, the party is on the third floor and you can hear the piano from two flights down. Fifty cents admits you to a suite of rooms, emptied of furniture, where people from all walks of life are moving slowly through rich smells and the glow of a single red light. On a table in the corner sits a disordered feast: fried fish, chicken, corn bread, chitterlings, pigs'feet, and more.

But the party seems to lean toward the back room because it's there that Willie the Lion sits at an old upright, surrounded by dancers bending and buckling. He's got his knees crossed, his derby tilted back, a cigar between his teeth. With his back arched, he beats the keys in a rumbling boogie rhythm, now and then looking down to cuss at the keyboard or coax it softly into his beat. Behind him sits Fats Waller, another of the great jazz "ticklers." After a chorus, Willie stops and turns to Fats: "All right, take it from there," and Fats sits down, hardly missing a beat, and tries to blow Willie away.

THOSE SOBBIN'-HEARTED BLUES

The sun is coming up, but true music lovers can't go back downtown before they have tried to get into the Vaudeville Comedy Club, an after-hours place below the Savoy. Not many whites get in, because it's a private club for entertainers and their friends. Jazz players go there after their regular gigs to escape the white "ofays" and be among people who really appreciate the music. Things start around 5 a.m. and usually get hot around 7. This morning, Bessie Smith is there. With a moaning sax in the background and a slow steady beat, she belts out, "I'm goin'to start walkin'`cause I got a wooden pair of shoes."

"Oh Lawd," cries a woman in the audience.

"Goin'to keep on walkin'till I lose these sobbin'-hearted blues."

She invades the room with screams and moans. "That wasn't a voice she had," recalled saxophonist Mezz Mezzrow, "it was a flamethrower licking out across the room." At 7 a.m. under the sleeping Savoy she sounds great, but it's time to call it a night, a day, or whatever.

As the streets brighten, the partygoers limp home to sleep off the effects of their revelry. For a few hours, in the moonlight, black performers have held white society in their spell. "Nothing America has created so far," wrote a German critic, "can bear comparison with the convincing power of Negro dancing and music."

But in the light of day, as black Harlem awakened and trudged off to church or work, the world still fell far short of an interracial paradise. As a Harlemite told one visitor, "They sing our songs, the whites do. They dance to the music we make. And yet, when it comes to renting us an apartment, they turn up their noses." In the end, Rudolph Fisher could only reflect cautiously on his homecoming. "Maybe these white people at last have tuned in on our wavelength," he wrote. "Maybe they are at last learning to speak our language."