John Milton Cage Jr. (September 5, 1912 – August 12, 1992) was an American composer, artist, and music theorist. A pioneer of indeterminacy 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 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.
Cage's teachers included Henry Cowell (1933) and Arnold Schoenberg (1933–35), both known for their radical innovations in music, but Cage's major influences lay in various East and South Asian cultures. Through his studies of Indian philosophy and Zen Buddhism in the late 1940s, Cage came to the idea of aleatoric or chance-controlled music, which he started composing in 1951. The I Ching, an ancient Chinese classic text and decision-making tool, became Cage's standard composition tool for the rest of his life.