and receive less attention. Unlike in jazz or rock, where artists often follow highly revered debuts with ongoing careers and wide explorations of their potential, in hip-hop the debut album is too often a career zenith.

Sliders include East Coasters Brand Nubian, Pete Rock and C.L. Smooth, Das EFX and Poor Righteous Teachers; West Coasters Digital Underground, Paris and Cypress Hill; old schoolers Eric B. and Rakim, Big Daddy Kane and Slick Rick; and new schoolers Arrested Development. The Slide doesn't always work itself out nicely: De La Soul have produced better albums with each release – concluding with their much-overlooked masterpiece, Bubloone Mindstate (1993) – but received less attention for each one. And some hip-hop giants may not have slid straight down, but after classic first, second and/or third albums, Jungle Brothers, Ice Cube, LL Cool J and Public Enemy have, in the past few years, released product far inferior to the work that first distinguished them.

The Slide can be blamed, in part, on artists' losing their connection with the street and satisfying the hunger that drove them as hopefuls with something to prove. But the nature of hip-hop carries an extra hurdle: Once your album comes out, your style – that is, all your vocal and musical innovations – is absorbed by artists and fans. In hip-hop it's always essential to make it new and very hard to renew the rush of first sonic love.

This is especially true because of the heavy pressure hip-hop puts on an MC's voice. Even among those who can flow, there are few with a God-given vocal quality that is compelling enough to allow more than short-term success as an MC. Unlike fans' reactions to their favorite rock and pop singers, the vocal familiarity of rappers often breeds contempt and boredom in the hip-hop community. That's why Black Sheep suddenly seem like a marriage that has run its course.

In 1991 rapper Dres and producer Mista Lawnge burst out with A Wolf in Sheep's Clothing and two large hits: "Flavor of the Month" and "The Choice Is Yours." Non-Fiction shows that Lawnge has matured as he laces tracks with interesting musical ideas like combining sharp percussion and high-note piano on "Let's Get Cozy" or letting an antique-sounding piano dominate "Summa tha Time." Though Dres is a good rhymer, he isn't worthy: His voice has neither the authority nor the