Napoleon Hill was born into poverty in 1883. As a teenager, he began writing as a reporter for small newspapers. He had visions of becoming a lawyer and did, in fact, enter law school, but financial constraints soon forced him to withdraw.

Then, in 1908, industrialist Andrew Carnegie commissioned him to interview hundreds of successful men and women, in an effort to prove his theory that success could be distilled down to a clear-cut formula.

Hill interviewed the most famous (and richest) people of the time, and "The Success Formula" was published in Hill's 1928 book The Law of Success. Hill reveals additional information on his success formula in the most famous of his works, Think and Grow Rich, published in 1937. It has sold more than 30 million copies to date.