Aimee Mann and Ted Leo toured together and discovered a musical chemistry that comes to brilliant light on The Both. Each songwriter contributes songs that sound personal, though all were collaborations in the end. The two then perform them with arrangements where both musicians give their input. Leo’s “Milwaukee” benefits from having Mann’s harmony attached; whether Mann and Leo are harmonizing or singing to each other in an emotionally charged call-and-response, their voices work well together (the key to any vocal duo). Leo adds his Thin Lizzy/hard rock guitars to Mann’s somber pop; they also cover the early Thin Lizzy tune “Honesty Is No Excuse,” and Mann lends a prettiness to Leo's power-punk dreams. Mann sweetens Leo’s “Volunteers of America,” while Mann’s “You Can’t Help Me Now” is toughened up by his snarling guitar work. While it’s often obvious who wrote the heart of each song here, it’s a great feeling when Mann and Leo are on equal footing during “The Prisoner,” “Bedtime Stories,” and “The Inevitable Shove,” and you’re not really sure.