Napoleon Hill's The Law of Success in Sixteen Lessons includes the True Philosophy upon which all Personal Success is Built. From Self Confidence to Imagination and all aspects of personality and habits, Hill spells out the steps to success. The Law of Success examines the power of personal beliefs and the role they play in personal success. "What the mind of man can conceive and believe, it can achieve." is one of Hill's hallmark expressions. How achievement occurs and the formula for achieving it are the focal points of Hill's The Law of Success and his later book Think and Grow Rich. Through the encouragement and support of Andrew Carnegie, Napoleon Hill studied the most successful men of industry in order to ascertain what traits each possessed. As part of his research, he interviewed Thomas Edison, Alexander Graham Bell, George Eastman, Henry Ford, Elmer Gates, John D. Rockefeller, Sr., Charles M. Schwab, F.W. Woolworth, William Wrigley, Jr., John Wanamaker, William Jennings Bryan, Joseph Stalin, Theodore Roosevelt, William H. Taft, Woodrow Wilson and Jennings Randolph. As a result of his research, the Philosophy of Achievement was offered as a formula for rags-to-riches success by Hill as a study course called The Law of Success.