Theory is the thing here, this is a study of theories. It does gesture at practices, but in ways that show how thinking and writing about improvisation are so beholden to theory that the book is full of claims that sound like they are being made by an alien, sent to study the human race and report back on the marvelous, intriguing strangeness of all these creatures.
La Tènes tools are more in the analogue realm, with their central trio playing ruggedly amplified hurdy-gurdy, scarecrow percussion, and bronchial Indian harmonium. Their four guest extensions will usually bring their amplified acoustic twelve-string guitar, electric bass, and cabrettessmall French bagpipes originating in the Auvergne region.
Sometimes the mood is doom, or at least some inchoate but powerful feeling. This may be best expressed by phrases that loop and mutate slowly, thickly, allowing for extended immersion in a kind of amniotic environment. Here, the repetition, the lack of typical progression or resolution, the indeterminacy, becomes a path to freedom or release.