Book excerpt: The peculiarly ambiguous character of applied psychology at the present time makes it appropriate to preface this book with an explicit statement of its purpose. The current development of the subject shows two widely divergent tendencies. The field covered by the subject is already large and is expanding rapidly, hence it has seemed best to limit the contents of the book to fundamental principles and the significant results attained in the three divisions of the field which have been most thoroughly explored, namely education, psychotherapy, and the psychology of industry, together with numerous illustrations drawn from other departments. The critical statement of principles is the most important part of the book, since it is by its misunderstanding of these that popular applied psychology usually goes astray. Throughout I have tried to keep the exposition as close as possible to common experience. Here psychology often succeeds only in giving precise form to what wise persons have long known, or reasons for what they have always done; but it is none the less desirable to have such exactitude and rationality scientifically established. This is perfectly genuine "applied psychology," though the fact is sometimes obscured in the atmosphere of experimental investigation. (PsycINFO Database Record (c) 2005 APA, all rights reserved).