Charles Francis Haanel (May 22, 1866 – November 27, 1949) is best known for his book The Master Key System which was published in 1912, when he was 46 years old.
In addition to the Master Key Syst...view moreCharles Francis Haanel (May 22, 1866 – November 27, 1949) is best known for his book The Master Key System which was published in 1912, when he was 46 years old.
In addition to the Master Key System, Haanel wrote other books including Mental Chemistry, which was published in 1922.view less