This is the last of the 199.x titles, a great diversion into those that were endlessly divisive amongst the C.P. cabal; so much so that common ground had to be carved out & explored... I'd heard legend of this internal-issue-only "White Label" GRM compilation, from trusted source "Ravi" Ben, of La Dame Blanche fame, but had never heard nor seen a copy until one literally landed in my lap at a soirée recently. Largely consisting of alternative & revised versions of prime 1973-era GRM pieces - the "Crème-de-la-crème" of the studio's offerings at this exact moment, at a particularly high point - this time capsule of a group of Composers in transition is something of a goldmine. 

Aside from the known pieces & excerpts - a few in alternate versions than appear elsewhere, others perfectly identical - there is one piece that was only ever issued here, Gilles Fresnais' "Etude en Bleu"; a fine slice of Pierre Henry-ish sproing and midrange synth clatter that would be worth the price of admission alone, yet within the context of the included pieces, selected essentially as working "calling cards" for each composer, it stands out, begging the question of what became of Fresnais in the long run. 

This is one for the extreme insider to this whole world of course; casual fans of Musique Concrète would be better suited to the various INA-GRM CD boxes, including "Archives GRM", & the career rundowns of Luc Ferrari, François Bayle, Bernard Parmegiani, and others' work. For the rest of us, this is an incredible insight reproducing a particular collection that you're highly unlikely to find out there in the aether...