The time has gone by when any one man could hope to write an adequate text book of psychology. The science has now so many branches, so many methods, so many fields of application, and such an immense mass of data of observation is now on record, that no one man can hope to have the necessary familiarity with the whole. But, even when a galaxy of learning and talent shall have written the text book of the future, there will still be need for the book which will introduce the student to his science, which will aim at giving him at the outset of his studies a profitable line of approach, a fruitful way of thinking of psychological problems, and a terminology as little misleading as possible. The present volume is designed to render these services.

Material contained in this book constitute an entirely new departure in the field of psychological study and experimentation.

This Book owes its origin to the indefinable sense of uneasiness and discontent into which I was thrown by the perusal of some of the best treatises on Logic. These treatises had failed to explain the nature of the logical or reasoning faculty, though purporting to indicate the laws which govern its proper functioning. Even the work of John Stuart Mill, which still remains in my opinion the best, was no more convincing than the rest. And the more I read of such books the less satisfied I became and the stonger became my desire to understand clearly what constituted reasoning. As for the psychologists I found to my surprise that they either omitted reasoning altogether, or alluded to it in a most superficial manner.

In the first three chapters of this book the elements of persuasion as a mental process are distinguished, and various forms of false persuasion in individuals and groups are described; it is shown how, from the very nature of the process involved, our persuasion of ourselves is only too apt to degenerate into self-deception, and how our persuasion of others may eaily assume the form of a deliberate attempt to exploit their mental or moral weaknesses. Chapter IV indicates how the tendencies of false persuasion may be counteracted, and on what lines persuasion may be rightly directed. Up to this point the subject is treated mainly in its psychological aspect. The subsequent chapters, which are closely related to, and follow naturally, the study of persuasion as a mental process, deal with persuasion more exclusively as a form of expression. In this part of the book special attention is given to such modern forms of propaganda as advertisements, newspapers, the cinematograph, the novel and the drama.

This book is based upon twenty-three years experience in local and convict prisons, and more particularly upon the work done, during the past three years, with offenders from Courts in Birmingham and the adjacent districts. The main object is to demonstrate how important is the throrough examination of the individual offender, especially in regard to his mentality. It is only by a great extension of this line of investigation that we can hope to solve the problems which criminality presents. A considerable part of the book is devoted to that new development of psychology which is known as psycho-analysis, and to the possible applications thereof to the investigation and treatment of offenders. The book includes a brief description of the theory and technique of psycho-analysis, so that the reader may not have to look elsewhere for an explanation of technical terms.

This little book is not a text-book of psychology. It is exclusively concerned with one particular psychological problem, a problem, however, that stands at the very centre of psychology. The relations between mind and body are analysed; that is to say, the following three psychedelic problems are successively raised: What is the mind? What is the body? What are the relations between mind and body? But it is only the third problem which is extensively dealt with; the first two are only briefly defined.