In the BBC Radio 4 programme, Archive on 4, John Cage – Composing Controversy, hosted by Gavin Bryars, Gavin interviews a number of people associated with Cage, including Caroline Brown and Christian Wolff. The show also benefits from a number of archive recordings of Cage and the people who knew him. Interviewees include some surprising choices, including the comedian Stewart Lee (who performed Cage’s Indeterminacy), John Paul Jones of Led Zepplin, and Brian Eno. Cage fans will know a lot of the stuff here, but it’s presented so well that it was consistently fascinating.
The online ‘Listen Again’ window for this has passed, unfortunately, but you can see a summary here, and perhaps catch it when it is repeated: http://www.bbc.co.uk/programmes/b01m9f5z .