100 years after John Coltrane’s birth, secret tapes are emerging. What can they tell us about jazz’s great rulebreaker?

<p>The sax star turned his back on fame to embrace free jazz. Caught on a tape machine hidden in an overcoat, newly revealed recordings show how he did it</p><p>In August 1965, at the height of his fame, saxophonist John Coltrane headlined the DownBeat jazz festival in Chicago. Tak