What are the ways to realize personal knowledge?

Li Xiaolai's Road to Wealth Freedom also mentioned selling patents and copyrights, that is, publishing books! Seven Habits of Highly Effective People was published in 1989, with global sales of more than 25 million copies and royalty income of nearly 1 100 million US dollars. Mr. Covey's speech costs as much as $30,000 an hour. But even so, it will take him nearly 3,000 hours to earn back the royalties-it will take at least three years. Patents and royalties do have high returns, but they are also ways to realize knowledge with higher thresholds.