Improvisation enjoys the curious distinction of being both the most widely practised of all mussical activities and the least acknowledged and understood. While it is today present in almost every area of music, there is an almost total absence of information about it. Perhaps this is inevitable, even appropriate. Improvisation is always changing and adjusting, never fixed, too elusive for analysis and precise description; essentially non-academic. And, more than that, any attempt to describe improvisation must be, in some respects, a misrepresentation, for there is something central to the spirit of voluntary improvisations which is opposed to the aims and contradicts the idea of documentation.
Derek Bailey, London, September 1991
in Improvisation, Its Nature and Practice in Music, de Derek Bailey [+info]