In Mental Chemistry you will learn how to improve your life by removing undesirable thoughts replacing them with more desirable ones. Charles F. Haanel uses the laws of Applied Chemistry to demonstrate how we can change our thoughts and lives. Just as in Applied Chemistry we can combine elements to create a new element we can combine thoughts to create new ones, better ones to become happier, and more successful. Mental Chemistry allows the change of material conditions by combining and appropriately utilizing the power of the mind. "Chemistry is the science which treats of the intra-atomic or the intra-molecular changes which material things undergo under various influences. "Mental is defined as "of or appertaining to the mind, including intellect, feeling, and will, or the entire rational nature." "Science is knowledge gained and verified by exact observation and correct thinking. "Mental chemistry is, therefore, the science which treats of the changes which material conditions undergo through the operations of the mind, verified by exact observation and correct thinking." Charles Francis Haanel was a noted American New Thought author and a businessman. He is best known for his contributions to the New Thought Movement through his book The Master Key System.