Think and Grow Rich, written by Napoleon Hill and released in 1937, is widely considered the most influential personal development and self-improvement book of all time. Published during the Great Depression, it synthesizes a "Philosophy of Achievement" based on Hill's stated research into hundreds of America's most affluent individuals, including Andrew Carnegie, Henry Ford, and Thomas Edison. The book argues that wealth and success are not products of luck or hard work alone, but are born from a highly disciplined, positive mindset that eliminates self-imposed limitations.