The Sound of Revolution combines Gilberto Gil's brilliant 1968 and 69 Tropicalia albums, Frevo Rasgado and Cerebro Electronico; joyous, extraordinarily inventive pop music made against a background of terrible political unrest in Brazil and in the shadow of both imprisonment and eventually exile both for Gil and his friend Caetano Veloso. The 1968 album is electrified by the meteoric Os Mutantes and both setsarranged by Rogerio Duprat who contributes a range of totally original textures and orchestration much as George Martin did with Strawberry Fields and Sgt Pepper.