Amazon.comAnthologist Quincy Newell's superb series continues with a snapshot of the tracks that underground hip-hop radio was banging in 1991. Rap was starting to splinter into factions: there was Will Smith (as the Fresh Prince) and the poppy side of Heavy D. in one corner, and in the other was the gunslinging school that was starting to develop into a gangsta culture on the West Coast (and that Run-DMC, surprisingly, allied themselves with). But there was also a third way--the politics-and-dancing route of Brand Nubian and Leaders of the New School--and a fourth, the wildly creative, nearly absurdist flow of cult favorites like Organized Konfusion and the Ultramagnetic MCs. And Chubb Rock, who ruled the underground's dance floors and broadcasts that year, shows up with three stone classics. --Douglas Wolk