Master Key System

The Master Key System is a personal development book by Charles F. Haanel. Originally a 24 week correspondence course released in 1912, it was published in this book form in 1917. Along with "e;The Science of Getting Rich"e;, by Wallace D. Wattles, the Master Key System was a primary inspiration for Rhonda Byrne's book and film "e;The Secret"e;. Charles F. Haanel was an American author, millionaire, entrepreneur, and businessman who belonged to the American Scientific League and several Masonic societies.