John Milton Cage (September 5, 1912 – August 12, 1992) was an American experimental music composer, writer and visual artist. He is most commonly known for his 1952 composition 4'33", whose three movements are performed without playing a single note.

Cage was an early composer of what he called "chance music" (and what others have labeled aleatoric music) — music where some elements in the music are left to be decided by chance; he is also well known for his non-standard use of musical instruments and his pioneering exploration of electronic music. His works were sometimes controversial, but he is generally regarded as one of the most important composers of his era, especially in his raising questions about the definition of music.

John Cage put Zen Buddhist beliefs into practice through music. He described his music as "purposeless play," but insisted: "this play is an affirmation of life—not an attempt to bring order out of chaos, nor to suggest improvements in creation, but simply to wake up to the very life we are living, which is so excellent once one gets one’s mind and desires out the way and lets it act of its own accord."

Cage was also an avid amateur mycologist and mushroom collector: he co-founded the New York Mycological Society with three friends. He was a long-term collaborator and romantic partner of choreographer Merce Cunningham.

Cage is also known as the inventor of the mesostic, a type of poem.

Several periods can be distinguished in the unfolding of John Cages work :
Works before 1940 are straight compositions which Cage himself did hardly count. A Flute Trio (3 parts) is the prime piece here.
Works up to 1955 (before '4'33"') are generally composed pieces, though by a constantly developing chance tecnique, and tones have set pitches. This is the period of the prepared piano,
Works dating 1955-1970 are very freestyle. The Variations-pieces are typical of this. 'For any ensemble with any instrumentation' is getting a common prescription, and it often gets quite noisy.
The legendary recording of the slow calculated destruction of a grand piano is a Variation piece. A Cage TV-performance of 'Water Walk' - available on YouTube - is another example.
The Works from 1970-85 gain more distinct expressions and instrumentations : music for branches or leaves or music that is basically readings. The period concludes with a series of collages called 'Europeras'.
1985-92 belongs almost exclusively to the 'Number' pieces, titled after the required amount of performers. These are ambient floating works of mostly long notes, reminiscent of his collegue Morton Feldman.