Mos Def's partnership with Talib Kweli produced one of the most important hip-hop albums of the late '90s, 1997's brilliant Black Star.

Consciously designed as a return to rap's musical foundations and a manifesto for reclaiming the art form from gangsta/playa domination, it succeeded mightily on both counts, raising expectations sky-high for Mos Def's solo debut.

He met them all with Black on Both Sides, a record every bit as dazzling and visionary as Black Star.

Black on Both Sides strives to not only refine but expand the scope of Mos Def's talents, turning the solo spotlight on his intricate wordplay and nimble rhythmic skills -- but also his increasing eclecticism.

The main reference points are pretty much the same -- old-school rap, which allows for a sense of playfulness as well as history, and the Native Tongues posse's fascination with jazz, both for its sophistication and cultural heritage.

But they're supported by a rich depth that comes from forays into reggae (as well as its aura of spiritual conscience), pop, soul, funk, and even hardcore punk (that on the album's centerpiece, "Rock n Roll," a dissection of white America's history of appropriating black musical innovations).

In keeping with his goal of restoring hip-hop's sociopolitical consciousness, Def's lyrics are as intelligent and thoughtfully crafted as one would expect, but he doesn't stop there -- he sings quite passably on several tracks, plays live instruments on others (including bass, drums, congas, vibraphone, and keyboards), and even collaborates on a string arrangement.

In short, Black on Both Sides is a tour de force by an artist out to prove he can do it all.

Its ambition and execution rank it as one of the best albums of 1999, and it consolidates Mos Def's position as one of hip-hop's brightest hopes entering the 21st century.