For many, this composer remains unknown, or at the very least unknown... And yet his music, strong and singular, is comparable to that of Ligeti, Xenakis and Stockhausen, and very often ahead of his contemporaries, such as his Musique pour cuivres, piano et percussion (1963), which bears strong resemblances to Xenakis's Eonta, written around the same period; Other works, such as Monumentum I (1967), seem to foreshadow the spectral movement so dear to France, and, like Stockhausen and Ligeti, he showed a clear desire always to transgress, to abandon what had been 'discovered' in order to explore other, as yet unexplored, territories. Thus, throughout his abundant oeuvre, from 1955 to 2007, we can distinguish very distinct and often disconcerting periods for those who thought they knew his music from a score written ten years earlier.