His Wikipedia page describes him this way:
John Milton Cage Jr. (September 5, 1912 – August 12, 1992) was an American composer, music theorist, writer, and artist. A pioneer ofindeterminacy in music, electroacoustic music, and non-standard use of musical instruments, Cage was one of the leading figures of the post-war avant-garde. Critics have lauded him as one of the most influential American composers of the 20th century. He was also instrumental in the development of modern dance, mostly through his association with choreographer Merce Cunningham, who was also Cage’s romantic partner for most of their lives.
It gives plenty of space to his music, but does not even mention his poetry. My online poetry course, however, is spending a whole week on him, and poets like him!
There are strong reasons to deny this is even poetry, since poetry has always involved sounds - which Cage is not interested in at all. What he was, before his time, was a computer – writing his poems using an algorithm. He was strictly in his head, and no one found this shocking. He wanted to get away from his gut, with all its disgusting messiness. And he had plenty of company.
My class at Penn U has an excellent introduction to his writing – with a priceless photo of him teaching at Oberlin College. Be sure to click on the photo.