Human Nature is a term most frequently used and yet little understood. The average person knows in a general way what is meant by it but very few are able to give an off-hand definition of the term or to state what in their opinion constitutes the real essence of the thought expressed by this familiar phrase. Human Nature means the nature of man or mankind. "Nature," in this usage, means: "The natural disposition of mind of any person; temper; personal character; individual constitution; the peculiar mental characteristics and attributes which serve to distinguish one person from another." Thus we see that the essence of the nature of mankind, or of a particular human being, is the mind, the mental qualities, characteristics, properties and attributes. Human Nature is then a phase of psychology and subject to the laws, principles and methods of study, examination and consideration of that particular branch of science. Human Nature expresses itself in two general phases: the phase of Inner States; and the phase of Outer Forms. These two phases, however, are not separate or opposed to each other, but are complementary aspects of the same thing. There is always an action and reaction between the Inner State and the Outer Form-between the Inner Feeling and the Outer Expression. If we know the particular Inner State we may infer the appropriate Outer Form; and if we know the Outer Form we may infer the Inner State. These two elements or phases, in their constant action and reaction, manifest the phenomena of Human Nature, and a knowledge of each, and both give to us the key which will open for us the door of the understanding of Human Nature. This is what this book is concerned with teaching you. The ability to read Human Nature puts you in a position of power.