Mark Twain obtained three patents over his lifetime.
Notes on verification
Confirmed by USPTO records and multiple independent reputable sources (Smithsonian, History.com) with consistent patent numbers and descriptions.
Sources
- Unswerving irregularity | USPTO (uspto.gov)
- https://www.smithsonianmag.com/history/mark-twains-patented-inventions-180958static/ (smithsonianmag.com)
- https://www.history.com/news/mark-twain-inventor-patents (history.com)