There’s unbridled joy and plenty of sweat on this buoyant 1980 album. On the Bob Marley-inspired reggae track “Master Blaster (Jammin’),” every instrument sounds like it's on springs, as Wonder makes a jubilant plea for unity. At the other end of the spectrum, “Lately” is one of his most aching ballads, with intimate vocals and a melancholy feel, while the ebullient “Happy Birthday,” a tribute to Martin Luther King Jr., is impossible to listen to without a smile on your face.