Napoleon Hill was one of the earliest writers of the genre of personal-success literature. The 12 riches of life include a positive mental attitude, sound physical health, harmony in human relationships, freedom from fear, the capacity of faith, willingness to share one's blessings, self-discipline, and economic security. A positive mental attitude is important because it converts the mind into the equivalent of an electromagnet which attracts the objects of one's dominating thoughts, aims and purposes. The Master-Key examines a combination of 17 principles that, when used together, will allow one to achieve the 12 riches of life. Those principles include the habit of going the extra mile, creative vision, personal initiative, enthusiasm and applying the Golden Rule.