It Takes a Nation of Millions was the sign that hip-hop had exploded like a grenade. A rap record as abrasive, hardcore, and eloquent as a JFK speech, the 1988 disc is one classic track after another: tense, multilayered, harmonically wild music. Chuck D. declaims like a master preacher with foil Flavor Flav's voice darting around his. They've got the desperate energy of people fighting for their lives, and everything from their pumped-up rhetoric ("Prophets of Rage") to the group's quasi-paramilitary organization to the sirens and sax squeals in nearly every track declares how urgent their mission is. It's a hugely influential album, and it still sounds fresh and frightening after all these years. --Douglas Wolk