Smog is an electro-acoustic work in five parts of equal duration, divided into several variable sequences. It was composed as the music score for the ballet Smog commissioned by the choreographer Michel Caserta. The work was premiered on October 18, 1974, by the Ensemble chorégraphique de Vitry at the Théâtre Jean-Vilar in Vitry-sur-Seine, Paris. As a musical work, it has acquired over the years the scope of a legend in the electro-acoustic-avant-garde scene, for its richness and value as a composition, the composer’s ingenious use of the means available at the time regarding the production of electric sounds, and their combination with natural sounds, as well as for the four-channel recording and live performance.