"It's a moonlighting album," Questlove says of the Roots' new LP with Costello. The adventurous hip-hop crew and the acerbic singer-songwriter bonded during a series of appearances on Late Night With Jimmy Fallon, where the Roots are the house band. They considered doing an album of reimagined Costello classics; instead, they cut a spacious, genre-bending funk set with a political charge. "There's a lot of dub stuff in there," says Costello. "It creates a challenge to make something which can hold your attention for the length of time it takes to tell a story, even though it doesn't progress in a conventional way."