After the Real Roxanne's three rapid-fire introductions to 1986's twelve-inch single "Bang Zoom (Let's Go-Go)," all three sassy, tough, and impressive, a wall of what sounds like loops of echoed steel drums and constant crowd noise forms a base for Roxanne's rhymes -- answered by sweet harmonies (provided by Eighties pioneers Full Force), blasts of keyboard, and adrenaline-charged scratches. This head-spinning single then breaks the rhythm down and changes it up countless times -- with a break for Lisa Lisa and Cult Jam-style singing by the rapper, keyboard goofing on the American Bandstand theme, Latin percussion solos, scratch leads, and ongoing interpolations from Warner Bros. cartoons. It was the golden age of the twelve-inch, and this all-but-forgotten jam stands as one of the most vital examples of the form, a likely inspiration for Eric B. & Rakim's classic "Seven Minutes of Madness" remix of "Paid in Full."

This cut comes four tracks into the Classics volume of Fat Beats and Bra Straps: Women of Hip-Hop, and by the time the song arrives it's plain that a richly textured and nearly secret history of popular music is unfolding. These first two volumes of Rhino Records' new three-disc collection (a third volume, New MC's, surveys the contemporary female hip-hop scene) devote nearly half (fifteen of thirty-one cuts) of their attention to the years before 1988, when the rap album came fully into its own; Public Enemy's It Takes a Nation of Millions to Hold Us Back, N.W.A.'s Straight Outta Compton, and Salt-n-Pepa's A Salt with a Deadly Pepa grabbed national attention and virtually defined the form.

Fat Beats uncovers many forgotten gems and offers even more insights into the crucial role of women in shaping hip-hop history and changing the face of the pop charts. (Women would take the charts like never before in Top 40 history by 1993, the majority of them R&B singers with hip-hop influences.) Battle Rhymes & Posse Cuts shows the tactics -- with Roxanne Shante's 1984 answer record to U.T.F.O.'s "Roxanne's Revenge" generating three answer records in response to it and ongoing imitation by other women -- most notably 1985's "The Show Stoppa (Is Stupid Fresh)," a response to party kings Doug E. Fresh and Slick Rick's "The Show" by Super Nature, later known as Salt-n-Pepa.

Classics is filled with revelations. Dimples D. opens the album with "Sucker D.J.'s (I Will Survive)," a tribute to her boyfriend Marley Marl that turns into her own gender-based version of "The Message." Sparky-D's hard-rhyming "Throwdown" should send many out looking for her sleeper album of 1988. 2 Much's "Wild Thang" is twice as hot as L.L. Cool J's remake, "Doin' It." "Runaway" shows the wisdom that made a teenage Shante fight so hard to make her voice heard. On "Can't Hold Back," Ice Cream Tee proves herself a hard, fast-talker with the skills of Kool Moe Dee or L.L., and a lyrical ambition that pits free speech and political unity against the violence of poverty -- drug abuse, gang battles, and hunger. And on the Battle album, Paulett and Tanya Winley's 1979 "Rhymin' and Rappin'" reveals the DNA for Missy Elliott's community-building jams at the dawn of hip-hop.

-- Danny Alexander

Jurassic 5
"Jayou" b/w "Without a Doubt"
(Rumble/Pickininny)

Black Star
"Definition" b/w "Twice Inna Lifetime"
(Rawkus)

Jurassic 5's name is a double whammy old-school joke. Not only does it hark back to the puffy-shirted, Afro Sheen-ed splendor of disco-era rap groups like the Funky 4+1 and Grandmaster Flash and the Furious Five, it also makes fun of how long ago and far away that stuff seems in the light of hip-hop's current pop-chart dominance. Now that the Earth has cooled and rock dinosaurs rise from extinction only when Puff Daddy and his special effects team want them to, what's an old-schooler to do but wait around for the inevitable Hip-Hop Hall of Fame induction ceremonies?

Well, Southern California's Jurassic 5 is figuring it can go out and make a lot of people happy. Their ensemble-rap style is winningly jubilant, if somewhat primitive compared to that of Wu-Tang Clan. Jurassic's sing-along vocals sometimes fall into nursery-rhyme territory ("Jayou" is pronounced "J-U," as in "J-U-R-A double-S I-C"), but their tuneful cadences -- especially as delivered by versatile lead rapper Charlie the Tuna (a mic stylist in whose hands lines such as "We conjugate verbs and constipate nerds" become funky little bass fills) -- could make even a hardcore gangsta want to bounce like a baby.

Even better is Jurassic's music. In a bit of overdue revisionism, Jurassic 5 recasts the old school in its original, experimental context, backing up their rhymes with mixes by avant-garde California DJ Cut Chemist (whose instrumental track "Lesson 6: The Lecture" appeared on both Om Records' Deep Concentration compilation and Jurassic 5's 1997 debut EP). His sparse but buoyant loops, subtly manipulated to defy expectations (check the interplay of "Jayou"'s insistent "Get Up, Stand Up"-quoting flute part with the song's spacious beat), help Jurassic 5 convey the spirit more than the letter of old school, and make good on their promise (expressed in "Without a Doubt") to "keep you open like a public bathroom."