The correspondence between composer John Cage and Peter Yates represents the third and final part of Cage’s most significant exchanges of letters, following those with Pierre Boulez and with David Tudor. Martin Iddon’s book is the first volume to collect the complete extant correspondence with his critical friend, thus completing the ‘trilogy’ of Cage correspondence published by Cambridge. By bringing together more than 100 letters, beginning in 1940 and continuing until 1971, Iddon reveals the dialogue within which many of Cage’s ideas were first forged and informed, with particular focus on his developing attitudes to music criticism and aesthetics. The correspondence with Yates represents precisely, in alignment with Cage’s fastidious neatness, the part of his letter writing in which he engages most directly with the last part of his famous tricolon, ‘composing’s one thing, performing’s another, listening’s a third’.