THE HIPHOP PRESS has been droppin' a lot of rap-to-rock analogies lately. The June issue of The Source had a thing about how Eminem is the modern Elvis, destined to be a "hero to most" for performing black music to white people. Then the July Vibe had a sidebar in their Mobb Deep feature defending the Queensbridge duo's lurid lyrics with an argument casting Havoc and Prodigy in the role of latter-day bluesmen. While it's nice to see the lightweights who write for those magazines (the melanin-infused flipsides of Spin and Rolling Stone--every bit as shallow, despite covering much deeper music) try something so sophisticated, they lack the music history knowledge to pull it off. Those analogies don't shed much light on hiphop's current situation.

Fortunately, there exists a handy new tool to aid in re-accessing Vibe and The Source's would-be hiphop analog. The moment when rhythm 'n' blues became rock 'n' roll is pinned down like a museum butterfly by Rhino Records' brand-new four-disc box set, Loud, Fast & Out of Control: The Wild Sounds of '50s Rock.

Was Elvis called "The King" because America couldn't handle black invention, or because he sang the newfangled music better than anybody else? Rhino puts his cover of Arthur Crudup's "My Baby Left Me" alongside key cuts by Little Richard, Chuck Berry, Joe Turner, and the rest, so you can decide for yourself. As one writer points out in Rhino's liner notes, the ebullition of R&B soul into the American mainstream coincided almost to the month with the first sparks of the Civil Rights movement. It's hard, after hearing the set, to deny that early rock was a lot less about stealing than about sharing. With the hillbillies feeding off the roadhouse scene and vice-versa (check the hee-hawin' bass line of Berry's first single, "Maybelline"), it was like a youth-oriented cultural exchange program.

Another of Rhino's liner noters ineptly tries to distinguish the dangerous-sounding tracks on the new comp from the contemporary hit-parade records by drawing an analogy (tricky business!) to modern music. To exemplify "dangerous" rock, this oldster cited Marilyn Manson and Hole. Nice try, Daddy-O, but the Establishment loves those two.

Mobb Deep are this era's representatives of the "just 22 and I don't mind dyin'" set. They're the most consistently vivid first-person ghetto rhymers the rap world has ever known, and have been since the 1995 release of their second album, The Infamous (Loud/RCA). At 24 they are the standard-bearers of hardcore hiphop, or "real rap" (their fourth album, Murda Muzik, is due this spring). There is no ghetto concept harder for outsiders (especially suburbanites) to understand than "the real." It refers to vérité reportage, but obliquely. Mobb Deep's music--a more stripped-down and resolved version of Wu-Tang's digital mechanism--is too hypnotic to deny a life of the mind. Imagination, for Mobb Deep, is a power to be turned in on itself. It's applied to the creation of propagandistic autobiography, in an acrobatic conversion of dreamlife into pure focus.

"Realness" speaks to this bootstrap process more than anything else. Its other oblique reference is to poverty--it's clear from context clues that to Mobb Deep, middle-class black life is phony. "African-American" activists decry this fact, as well they should, because it represents the opposite side of a very old and heated debate over tactics, dormant in recent years, within the black population. It's the fight W.E.B. DuBois' "talented tenth" won over Booker T. Washington's model, Up From Slavery. How to rise from the depths of poverty and despair? Mobb Deep and their ilk use the terminology of The Godfather instead of that of Washington, D.C., but hardcore's message of self-sufficiency amid chaos, refusing to trade mainstream acceptance for a homegrown code of honor, is unmistakable.

Seen this way, Eminem is not like Elvis because he's stealing the soul, but because he, too, is real. But to foresee a wave of equally authentic white rhyme-reporters is to deny the isolation of America's ghettos. In the wake of DuBois and his assimilationist progeny, they have become cultural islands. Hiphop's interghetto network encompasses the last vestiges of the sort of unassimilated energy that, in the mid-1950s, gushed out of the Baptist South like freshly tapped crude. Eminem alone broadcasts to white America from that island, making him one-of-a-kind in a whole different way than Elvis the King, who relied on his voice on loan from God.

Mobb Deep's got the blues, all right, but their music is more African than anything those blind sharecroppers put on wax in the '20s. And they're aware of what's lost when soul is shared, in a way that past generations couldn't understand. Astoundingly, a legacy that Mobb Deep do, in fact, continue turns up on the Rhino set, during a profoundly intense three minutes called "Bo Diddley." Sharing the rhythm and (singular) chord structure of (also included) "Who Do You Love?" and "Hey! Bo Diddley," only this one artifact of the spring of 1955 resonates with the uncompromising self-extension of Mobb Deep's exhortations at the whirlwind. It's partly in the production. The drums, deadpan but thunderingly human, mediate between a guitar's depiction of slashing rain and fire on one side and the voice that somehow knows their language on the other.

People still face the horror of untamed nature and survive, and the stories they bring back still don't inspire comfort. Except, that is, in those in danger.