Why did Margaret Mitchell write only one novel, despite its massive success?

For many years after Gone With the Wind’s release in 1936, Mitchell insisted that, because of the disruption its popularity caused in her life, she had no intention of ever writing again. She spent much of her time after its publication responding to fan letters and managing what quickly became an international publishing empire, primarily by taking legal action against foreign publishers who released unauthorized editions or failed to meet her standards. By the late 1940s, though, she was considering ideas for a new novel. Her sudden death in 1949 meant she never published another book.