Christian Wolff presented Cage with a copy of the I Ching, which is a text that uses a symbol system to identify order in chance events.
Christian Wolff (composer) (born 1934), American composer of experimental classical music The Wolffs published a series of notable English translations of European literature, mostly, as well as an edition of the I Ching that came to greatly impress John Cage after Wolff had given him a copy. The interpretation of the readings found in the I Ching is a matter which has been endlessly discussed and debated over in the centuries following its compilation, and many commentators have used the book symbolically, often to provide guidance for moral decision making as informed by Confucianism, Taoism and Buddhism. 
