Think and Grow Rich by Napoleon Hill, promoted as a personal development and self-improvement book. Hill writes that he was inspired by a suggestion from business magnate and later-philanthropist Andrew Carnegie. While the book's title and much of the text concerns increasing income, the author insists that his philosophy can help people succeed in any line of work, to do and be anything they can imagine. First published during the Great Depression, the book by Hill's death in 1970 had sold more than 20 million copies. By 2015 more than 100 million copies had been sold worldwide. It remains the biggest seller of Napoleon Hill's books. BusinessWeek magazine's Best-Seller List ranked it the sixth best-selling paperback business book 70 years after it was published. Think and Grow Rich is listed in John C. Maxwell's A Lifetime «Must Read» Books List.