Tag: personal development industry origins

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The Master Key System: The Forgotten Book That Built the Personal Development Industry

In 1919, a struggling magazine editor in Pennsylvania sat down and wrote a letter to a St. Louis businessman he had never met. He wanted to thank him. Years earlier, broke and directionless after a string of failed ventures, he had stumbled onto a 24-week mail-order course that arrived, lesson by lesson, in a plain […]

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