The Master Key System

"The Master Key System" is a personal development book by Charles F. Haanel that was originally published as a correspondence course in 1912. Though originally a 24 week correspondence course, it was published in book form in 1916.

"The Master Key System" is the only clear, concise, comprehensive, definitive, distinctive, cogent, and scientific presentation of the Creative Power of Thought ever formulated by any one person at any one time.
"The Master Key System" is a system that teaches the ultimate principles, causes, effects, and laws that underlie all attainment and success. When you want to attain something, "The Master Key System" will show you how to get it.
The book describes many New Thought beliefs such as the law of attraction, creative visualization and man's unity with God, and teaches the importance of truth, harmonious thinking and the ability to concentrate. Each of the 24 chapters contains an introduction, followed by a sequentially numbered section which includes an exercise towards the end, followed by a section with questions and answers.
Over 90% of the value of this book comes from doing the daily exercises prescribed and, without actually spending the few minutes each day on them, few results if any will come, even from a deep understanding of these words.

Charles F. Haanel was an American author, millionaire, entrepreneur, and businessman who belonged to several Masonic societies, the American Scientific League, The Author’s League of America, The American Society of Psychical Research, the St. Louis Humane Society, and the St. Louis Chamber of Commerce.
Napoleon Hill, the author of "Think and Grow Rich" also credits Charles Haanel and this book for his success.

"The Master Key System" is the source of Rhonda Byrne's inspiration for the book and the film "The Secret" (2006).