** Bilingual edition (English / French) 35 x 27 cm (spiral bound), 21 pages (ill.)  ** Facsimile scores and documents about the creation premiered on 28 February 1977 at the Palais des Arts, Paris, by Bernard Parmegiani. "After having used different compositional writing styles (letting the notion of sounds' 'nature' appear through sounds originating from all different types of things, especially in 'De Natura Sonorum'), there still remained the ever-abundant world of the noises that result from human activity, which I'll call "artificial" so as not to confuse with "natural". These noises are the clue to life which is, whether close or far, physical or temporal, in the present. Natural sounds possess a power that speak to us at different levels. They reveal a force, an energetic dynamism, which escapes us and yet which we attempt to grab a hold of through the bias of the internalized act of listening. Being able to record them facilitates a progressive logic to their existence. Through our interpretations and our expressions when listening to sonic material, we initiate a metamorphosis from the interior to the exterior. The notion of metamorphosis, or transformation, is one of the principles that directs the shape of this set of movements.

The transformations between sounds reflect their evolution:
- transformations from liquid to solid (water / ice); from solid to gas (combustion / fire)
- back-and-forth within the flux / reflux of space (waves); within the body (breathing in / breathing out)
They can also indicate passages:
- from the inside to the outside (door or portal)
- from the individual to the collective (one person / crowd)
The object which is perceived is therefore not entirely that which we might have taken it to be. Music also brings some of us together while it pulls others away. To each their own interior 'sound'."

French composer Bernard Parmegiani (1927-2013) is an essential figure of contemporary music. His work, very diversified, is essentially devoted to electroacoustic music of which he is one of the pioneers. He was a founding member of the Groupe de recherches musicales (GRM) from 1960 to 1992.