From one of the early giants in the self-help field, Napoleon Hill became an instant bestseller with his 1937 publication of Think and Grow Rich! “Keys to Success” draws on Hill’s nearly two-decades of research — including interviews with business titans and patrons Andrew Carnegie, Henry Ford, and John D. Rockefeller. He distilled what he learned into 17 “keys” to success. These would later be emulated in almost every self-help book to come after; things like discovering a definitive purpose, controlling your attention and maintaining sound health. He also includes some invaluable gems that aren’t touched on as much anymore: controlling your enthusiasm, using “cosmic habitforce,” and applying faith (in the secular sense) to all of your undertakings.