Why do most people work hard their whole lives and still never get rich?

In 1908, steel billionaire Andrew Carnegie handed a young reporter named Napoleon Hill an impossible assignment: spend the next 20 years studying the richest, most successful people alive, then extract the exact formula they all followed.

Hill interviewed over 500 of them. Edison. Ford. Rockefeller. And he discovered something startling: they all ran the same mental process, whether they knew it or not.

In 1937 he published it as Think and Grow Rich. Nearly a century later, it's still the blueprint underneath almost every success philosophy that followed.