Conversation so far:
What is The New Yorker magazine?
The New Yorker is an American weekly magazine featuring journalism, commentary, criticism, essays, fiction, satire, cartoons, and poetry.
What happened in 1992 to Art Spiegelman?
Art Spiegelman was hired by Tina Brown as a contributing artist in 1992 for The New Yorker magazine.

Question: Why did he leave?
Self-contained rewrite: Why did Art Spiegelman leave The New Yorker magazine?