Alongside Caetano Veloso's early albums, Gilberto Gil's late-1960s work, namely `68's FREVO RASGADO and `69's CEREBRO ELECTRONICO, offer a primer in the joys of Tropicalia. THE SOUND OF REVOLUTION pairs these two Gil classics, representing the artist's glorious hybrid of traditional Brazilian forms, psychedelia, and British and North American rock. Wildly imaginative and infinitely listenable, it's no overstatement to call these discs pop masterpieces. Those unfamiliar with Gil should do themselves a favor and pick this up.