THE art of understanding human nature is the art of understanding the dynamic patterns of human conduct. Alfred Adler has given us the key to this understanding in his monumental contributions to modern psychology, but before the compilation of this volume of case histories the student of the methods of Individual Psychology has been compelled to search for his case material among the German publications of Adler and his pupils. Many of these published cases deal with conditions germane to continental environments, but puzzling to American readers. The principles and practice of Individual Psychology, however, are universally valid in their application, as this volume of purely American cases demonstrates. The essential unity of all human conduct is amply adduced by the success of the Viennese psychologist and educator in the analysis and treatment of these cases brought to his clinic, without previous selection or limitation, at the New School of Social Research, during his lecture season of 1929. They are typical of cases found in the schools and child-guidance clinics of every large American city. Some of the cases were brought in by New York physicians, some by psychologists, but the majority by New York school teachers who were puzzled by problem children under their care. All of the cases were worked up more or less thoroughly according to an outline for the study of problem children written originally for the child-guidance clinics which Dr. Adler established in Vienna. Although for the sake of brevity the headings have not been incorporated in the text, the arrangement will be obvious to any student who desires to prepare a case history for study. The method of presentation was as follows: a physician or teacher who had studied a problem child prepared the history according to the protocol. Dr. Adler, without having seen the child or previously discussing the case with the teacher, read the case history, sentence by sentence, making his deductions as the case progressed. Occasionally Dr. Adler was misled by a statement in the protocol, but in the vast majority of instances he built up a dynamic picture of the child's personality, often predicting the findings with uncanny insight into the ways of a child's soul, always illuminating the history with his gentle sympathy for the actors in the human drama under discussion.