More than 15 years into their career, Philadelphia hip-hop group the Roots approached their long-awaited ninth album with nothing to prove. That security doesn't stop the Roots from challenging the boundaries of their sound on "How I Got Over," their third and best effort on Def Jam. The track "Right On" spins a winning old-school vibe around the hook to Joanna Newsom's "The Book of Right-On," while lead single "Dear God 2.0" injects socially conscious rhymes into a Monsters of Folk track. The riffs on indie music work surprisingly well, but the Roots are still at their sharpest when offering a reflective, soul-tinged version of street rap. "I'm ready . . . to start acting my age/And part ways with the Black Thought from back in the days," Roots frontman Black Thought raps over Ahmir "?uestlove" Thompson's booming percussion on the song "Now or Never." "How I Got Over" finds the Roots acting as elder statesmen in hip-hop, but its mix of nifty experiments and straightforward rap eliminates any sense of predictability.