Uncle Tom's Cabin was no literary masterpiece but it was a culture-bearing book. It came at a time when the entire culture was about to reject slavery. People seized upon it as a portrayal of their own new values and it became an overwhelming success.
The success of Zen and the Art of Motorcycle Maintenance seems the result of this culture-bearing phenomenon. The involuntary shock treatment described here is against the law today. It is a violation of human liberty. The culture has changed.
Zen and the Art of Motorcycle Maintenance (1974) - Afterword (1984)