Oliver Napoleon Hill (October 26, 1883 – November 8, 1970) was an American self-help author. He is best known for his book Think and Grow Rich (1937), which is among the best-selling self-help books of all time. Hill's works insisted that fervid expectations are essential to improving one's life. Most of his books were promoted as expounding principles to achieve "success".

Hill is, in modern times, a controversial figure. Accused of fraud, modern historians also doubt many of his claims, such as that he met Andrew Carnegie and that he was an attorney. Gizmodo has called him "the most famous conman you've probably never heard of".

Napoleon Hill was a prominent self-help author and motivational speaker best known for his book "Think and Grow Rich." However, Hill's life before achieving success was tumultuous, to say the least. Born in a one-room cabin in Virginia, Hill's parents were James Monroe Hill and Sarah Sylvania Blair, and he was the grandson of James Madison Hill and Elizabeth Jones. His father was an unofficial dentist and also a moonshiner. Hill's mother died when he was nine, and his father remarried two years later to Martha, who helped to civilize him.

At the age of 13, Hill began writing as a "mountain reporter," initially for his father's newspaper. At 15, he married a local girl who had accused him of fathering her child, but the girl later recanted the claim, and the marriage was annulled. At 17, Hill graduated from high school and moved to Tazewell, Virginia, to attend business school.

In 1901, Hill accepted a job working for Rufus A. Ayers, a coal magnate and former Virginia attorney general. According to author Richard Lingeman, Hill received this job after arranging to keep confidential the death of a black bellhop whom the previous manager of the mine had accidentally shot while drunk. Hill left his coal mine management job soon afterward and enrolled in law school, although he withdrew due to a lack of funds. Later in life, Hill would use the title of "Attorney of Law," although his official biography notes that "there is no record of his having actually performed legal services for anyone."

Hill's life was marked by personal turmoil as well. In 1903, he married Edith Whitman, and in 1905, their child Edith Whitman Hill was born. Their marriage was fraught with alleged physical abuse by Hill, who also frequented prostitutes. Edith filed for divorce in 1908, and at the proceedings, Hill's friends and business partners testified to his affairs with prostitutes. It was during this time in 1908 that Hill claims to have had a pivotal conversation with Andrew Carnegie, although there is no record of the two meeting, and Hill spent much of the year on the run from the authorities.

Following the exposure of his fraud in Alabama, Hill fled to Washington, D.C., where he dropped his first name, Oliver, and began going by Napoleon Hill. In 1909, he founded the Automobile College of Washington. The college assembled cars for the Carter Motor Corporation, which declared bankruptcy in early 1912, leaving students unpaid for their labor. During April 1912, the automobile magazine Motor World accused Hill's college of being a scam and derided its marketing materials as "a joke to anyone of average intelligence." Following the bankruptcy of the Carter Motor Corporation, Hill pivoted the organization to teaching people how to sell cars rather than make them. In this form, it resembled a modern multi-level marketing company.