This volume on psychotherapy belongs to a series of books which I am writing to discuss for a wider public the practical applications of modern psychology.<br /><br />The chief aim of this book is twofold. It is a negative one: I want to counteract the misunderstandings which overflood the whole field, especially by the careless mixing of mental and moral influence. And a positive one: I want to strengthen the public feeling that the time has come when every physician should systematically study psychology, the normal in the college years and the abnormal in the medical school. This demand of medical education cannot be postponed any longer.