The most chilling pop single pumping out of America's radios this year is not sung, but spoken urgently over a hypnotically terse rhythm track. It walks a listener down mean inner-city streets where young urban blacks who can't even hope for hope live. Titled "The Message," and performed by Grandmaster Flash and the Furious Five, it is really a warning: "Don't push me 'cause I'm close to the edge/I'm trying not to lose my head/It's like a jungle, sometimes it makes me wonder/how I keep from going under."

The medium is rap; the audience is rapt. And because of hits such as "Freedom" and "The Message" and Kurtis Blow's "The Breaks" and "Tough," America has discovered an apparently new phenomenon with roots easily traceable to the South Bronx and Harlem. Since the mid-'70s, that war zone has also inspired such cultural curiosities as graffiti art and break dancing (to that portion of records where bass and percussion work out), insulated exuberances gone public. Tonight, 20,000 people will fill the Capital Centre as Grandmaster Flash and Blow, the two biggest names in the rap world, usher in the new year with the annual Party With the Stars.

But the style, verbal bantering as opposed to singing, is really deeply ingrained in Afro-American culture, says Washington-based singer/songwriter Gil Scott-Heron, who has had several rap-style hits, recently with "B-Movie," but as far back as 1969 with "The Revolution Will Not Be Televised."

"The oral tradition is just that, a tradition that relates back for hundreds of years in our culture, and I don't feel it's anything new if it's been going on for hundreds of years," says Scott-Heron. "The original African tradition was based on the griot, the oral historian. In lectures, I try to tie in the oral phenomenon going on now with Dr. Alex Haley's going to Gambia and looking for evidence of Kunta Kinte; it's a piece of oral history that hooked Haley up with his roots and by proxy hooked a lot of us up with our own backgrounds and forefathers."

Scott-Heron traces the griot tradition to the spontaneous rhyming of calypso artists, to poet Don L. Lee and Nation, Nikki Giovanni's work with the Choir in New York and, in the late '60s, to Imamu Baraka (Leroi Jones) and his Kaumba House, where poets "performed in the oral tradition accompanied on rhythm instruments, flutes. That was the first time I ever came into contact with anything of that nature.

"Using the kind of rhythmic background and musical accompaniment that rappers are using now might well be considered new, but something that's been going on that long is hard to identify as a new phenomenon."

Other antecedents: the jazz singing of King Pleasure, James Brown, Bo Diddley, the blues, the on-air jive of '60s radio personalities. "Black people, maybe unconsciously, came across something that has always been a part of our street corner tradition," Scott-Heron explains. "The way we rap has always been described as rhythmic and inventive, colorful and descriptive; it seemed a waste to have all that talent in a given direction and not be able to use it to advantage. I hope we use those art forms for something that is more informative than entertaining, rather than something that would attempt to break our arms patting ourselves on the back and telling ourselves how bad we are and how cool we are."

Modern rap, which until "The Message" tended to be strictly party and boasting music, has been slowly building its audiences, to the point where (in watered-down form) it has been used in national advertising campaigns to sell portable stereo equipment (Panasonic), a soft drink (Mello Yello) and a new model car. But the question for many years, one that remains unanswered, is "will it spin in Peoria?"

"It's hard for new things to get exposed outside of their birthplace," says Kurtis Blow, who had one of rap's first national hits two years ago with "The Breaks." "And it was so hard for us to travel; it's hard to take a small part of the world where something is created; how do you get it exposed? I've been rapping since 1974. I wanted to put hard-core messages but . . . I thought that radio would just blank off to that. But since 'The Message' came out, I don't know. Maybe we can say anything we want to now."

There are actually two parts to rap: the rappers and the deejays. It started with the deejays who spun discs in the South Bronx and Harlem; legendary figures such as Eddie Cheeba, Starski, and Cool Deejay Hurc filled the dance clubs with their echo-chambered patter. The regular clubs were analogous to Minton's, where bop originated in the late '40s and early '50s. Some deejays, such as Afrika ("Planet Rock") Bambaatta, even inspired a loose-knit alternative to street gangs, the Zulu Nation, which established music and dance as an alternative to fighting.

The deejays were major figures in the community, "almost superheroes," says Grandmaster Flash (real name: Joseph Saddler). "They had the reputations when I was coming up. That's what really influenced me to try a new style of mixing: I saw where they had the power over the people there in the sound system. But there was an element left out."

"In the beginning you just had radio jocks coming out to discos and making announcements," says Blow. "Then it evolved into the speaker talking more, then into more of a rhythm type thing. Same thing with the deejay behind him, the engineer who held it together for the whole party. Back in 1974, a deejay used to take a specific part of a record and keep it going for a long time, hold that beat so the rapper could rap on top of it; then it evolved into the deejay holding the beat together and also cutting the record, spinning it backwards and forwards and making a beat of his own. And then it evolved even further into what we now call the quick mix, where the deejay would take the turntables and spin the records backwards and play a beat from one turntable to another very fast."

There was no better stereo sorcerer than Flash. On "The Adventures of Grandmaster Flash on Wheels of Steel," he sets down his philosophy; "Like dynamite before it blows/who needs a band when the beat just goes BOOOOOOOM . . ." Like the others, he had mastered "the breaks," the 30- to 60-second portion of dance tracks where bass and percussion worked out. On "Steel" alone, Flash dissected and reassembled Blondie's "Rapture," Chic's "Good Times," Queen's "Another One Bites the Dust" and several other rap hits. Like jazz saxophonist Charlie Parker, Flash could reinvent sound on the spot by reshuffling the recorded components with quick cut rhythms; his twin and triple turntable moves and intuitive sense of timing are legendary, with headphones for each turntable.

Flash made his reputation in the South Bronx with rap parties in an abandoned apartment in his building and by hot-wiring street lights in the public parks for free concerts. As his turntable technique became more complicated, the Furious Five joined up and took over the front vocal role full time.

"That's how it started before the records came," says Blow. "All the rappers really talked about was themselves, boasting about partying, partying and partying. Rappers got into what I call the Bo Diddley Syndrome: He'd always talk about himself--Bo Diddley the gunslinger, Bo Diddley the astronaut, Bo Diddley this, Bo Diddley that. When I turned 20, I started to get out of that. I thought people needed just a little bit more than party, party, party. When I made my first record, I didn't want to talk about Kurtis Blow, I wanted to talk about other things in life."

Typically, it was a white rap tune, Debbie Harry's "Rapture," that opened people's ears to the style. There's a long history of black cultural innovations being co-opted by white artists, but Harry and her group, Blondie, did take rap outside its community (and even credited the rap masters in the songs lyrics); they also talked it up in interviews and for the first time rap artists started getting booked outside Harlem and the South Bronx. "It doesn't bother me," says Blow. "That's how it happened with rock 'n' roll and reggae; but it adds to the acceptance of rap music as a whole."

There had been other "serious" rap hits in recent years, including Scott-Heron's "B-Movie" and Brother D's "How You Gonna Make the Black Nation Rise" ("Agitate, agitate, agitate"). Like much minority music, it still originates from small independent labels such as Sugarhill, which had the first national rap hit in 1979 with the Sugarhill Gang's "Rapper's Delight."

But "The Message" was the first harsh reflection of the street life that inspired the music. "We thought it was too low key," says Flash. "We thought the people really didn't want to hear that. 'The Message' starts with the worst of things, goes around everyday living and ends in death. I never really thought that people would want to hear it."

"The Message II" has just come out and is more upbeat, talking about being strong and surviving. Kurtis Blow feels that "The Message" will have a lasting effect. "When kids are kids, they always think about party, party all the time. But as they grow older, they start to get more serious. Disco left the kids out; this is an outlet for the kids. They needed some place to party, too."

Scott-Heron agrees. "Anything that the young folks get off on and get something positive out of, I'm in favor of. It is time to get serious. Whether young folks can recognize that or not is a tough question. Whether or not the young folks are looking at it or not, they're going to have to look at it in a minute. I think it's our job and our responsibility as artists to help prepare people for what's going to be happening tomorrow, rather than describing to them what went down yesterday."