Definition of Psychology of Management. - The Psychology of Management, as here used, means, - the effect of the mind that is directing work upon that work which is directed, and the effect of this undirected and directed work upon the mind of the worker. Importance of the Subject. - Before defining the terms that will be used more in detail, and outlining the method of treatment to be followed, it is well to consider the importance of the subject matter of this book, for upon the reader's interest in the subject, and his desire, from the outset, to follow what is said, and to respond to it, rests a large part of the value of this book. Value of Psychology. - First of all, then, what is there in the subject of psychology to demand the attention of the manager? Psychology, in the popular phrase, is "the study of the mind." It has for years been included in the training of all teachers, and has been one of the first steps for the student of philosophy; but it has not, usually, been included among the studies of the young scientific or engineering student, or of any students in other lines than Philosophy and Education. This, not because its value as a "culture subject" was not understood, but because the course of the average student is so crowded with technical preparation necessary to his life work, and because the practical value of psychology has not been recognized. It is well recognized that the teacher must understand the working of the mind in order best to impart his information in that way that will enable the student to grasp it most readily. It was not recognized that every man going out into the world needs all the knowledge that he can get as to the working of the human mind in order not only to give but to receive information with the least waste and expenditure of energy, nor was it recognized that in the industrial, as well as the academic world, almost every man is a teacher.