What are the most legit books on becoming a millionaire?

Legit meaning:

1. They got rich before writing the book, not from the book. They also don't have any courses or upsells.

2. They didn't get rich from the stock market or index funds.

3. They didn't get rich from real estate.

4. They got rich from business. Either from starting from nothing and then eventually selling the business or from buying an already established business, improving it, then selling it.