After a 2005 collaboration on the pensive, pleasant “Road to Zion,” from Marley’s Welcome to Jamrock album, Bob’s youngest son and Nas concoct an entire suite of rap/reggae crossover devoted to black nationalism and African liberation. At times, the results are a bit aimless; even a cute kids’ chorus can’t save “My Generation” from Joss Stone’s wailing or Lil Wayne’s awkward motivational turn. When the two principles catch a groove, though, it’s impressive, as on the unrelenting organ buzz of leadoff single “As We Enter” and theriotous “Nah Mean.”
