Conversation so far:
What wider cultural renown was Karlheinz Stockhausen known for?
Karlheinz Stockhausen, along with John Cage, is one of the few avant-garde composers to have succeeded in penetrating the popular consciousness.
How was Karlheinz Stockhausen able to penetrate the popular consciousness
The Beatles included Karlheinz Stockhausen's face on the cover of Sgt. Pepper's Lonely Hearts Club Band. This reflects his influence on the band's own avant-garde experiments.
Why did the Beatles include Karlheinz Stockhausen on the album cover Sgt. Pepper's Lonely Hearts Club Band?
This reflects Karlheinz Stockhausen's influence on the band's own avant-garde experiments as well as the general fame and notoriety he had achieved by that time (1967).
How did Karlheinz Stockhausen influence the Beatles's avante garde expirements
In particular, A Day in the Life and Revolution 9 were influenced by Karlheinz Stockhausen's electronic music.
Did Karlheinz Stockhausen influence any other musicians besides the Beatles
English conductor Sir Thomas Beecham was asked Have you heard any Karlheinz Stockhausen?, he is alleged to have replied, No, but I believe I have trodden in some“.
In what other ways was Karlheinz Stockhausen influential in cultural renown besides music
Karlheinz Stockhausen's fame is also reflected in works of literature. For example, he is mentioned in Philip K. Dick's 1974 novel Flow My Tears, the Policeman Said.

Question: Did he write?
Self-contained rewrite: Did Karlheinz Stockhausen write?