Any shorthand history of popular music will inevitably point to Nirvana's 1991 album Nevermind as the turning point at which certain then-bubbling-under segments of the youth culture became a dominant commercial force. But as important as Nevermind is, it didn't really set the tone for the rest of the decade the way the Beastie Boys' 1992 album Check Your Head did. Still dodging the novelty-act tag that allowed 1989's brilliant, now-revered Paul's Boutique to be ignored, the band started playing instruments again on tracks that touched on their rough, hardcore roots and their love for funky, '70s-style instrumentals, while never creating any doubt that Check Your Head was at heart a hip-hop album. But what mattered more, and allowed for some clumsy patches to be forgiven, was the attitude. With generous, wide-ranging lyrical and musical references, Check Your Head was almost an ethical stance. If the central hippie axiom is "Do your own thing," it's a view the group seems to share. But while the hippie version of doing your own thing generally amounts to doing what all the other hippies do (i.e., very little), the members of the Beastie Boys have taken it much more literally, both on record (with the more-refined Head follow-up Ill Communication) and off (with philanthropic activities and the Grand Royal magazine and label). Like punk rock, Lee "Scratch" Perry, John Woo, Kojak reruns, archaic video-game systems, and The Diabolical Biz Markie? Fine, do something with it. Want to save Tibet? Work at it. All of which forms the background of the Beastie Boys' long-delayed new album Hello Nasty, which may be the fullest embodiment of the group's liberating, challenging aesthetic to date. A dense disc, Nasty manages to sound like both an homage to the group's roots in early rap and music from the future. Writing rhymes together for the first time since Boutique, the group sounds as tight as it ever has. The straight-out rap tracks (more prominent here than on Nasty's two predecessors), like "Super Disco Breakin'," "Three MC's And One DJ," "Putting Shame In Your Game," and "The Negotiation Limerick File," are thrillingly old-school, with Run-D.M.C. serving as a source both for samples and musical, lyrical, and stylistic inspiration. At the same time, the group continues to be unafraid to experiment. "Song For The Man," "And Me," and "I Don't Know" mark the Beastie Boys' first real foray into singing, not counting the shout-barking of their hardcore tracks. While the vocal athletics of, say, Desmond Dekker are never brought to mind, the singing is expressive and perfectly in tune with the mood of the album. Though guest vocal tracks by Brooke Williams and Lee Perry, and the seemingly Santana-inspired instrumental "Song For Junior," might be better confined to B-sides, it's not as if they sound out of place, either. On an album as ambitious as Hello Nasty, not a lot would. This is a solid Beastie Boys record that, like those that came before it, should take a while to digest and be all the richer for it. It may not be a grand statement like Boutique or Headand, if the band would spend a little less time between albums, the pressure to produce such things might let up a littlebut it's still pretty grand.