Most peculiar: a tape recording of composer Edgar Varèse conducting a workshop of Jazz musicians in the year 1957.
It might be the first free jazz recording (totally unissued) of History of Music. Varèse might have influenced jazzmen or was he only aware of what was happening on the jazz scene? No matter of the answer, it’s a bomb, as this music is 3 years earlier than Free Jazz by Ornette Coleman!
Hat tip: Chris Atwood.
Update: if the link above gives you trouble, try this one and scroll down to the bottom for the Varèse entry.