This is a compilation of 38 papers presented in 5 sessions. Although the sessions have not been given general titles, the first dealt chiefly with anatomic and experimental considerations; the second with birth injuries and natal and prenatal influences; the third with metabolic factors; the fourth with congenital conditions; and the fifth with psychoses in children. The discussions following each session are reported. About half of the papers are provided with summaries, and some are so short that no summary is needed. Most of the papers include a list of references. One paper is in French and one is in German. The rest are in English. Many of the papers are appropriately illustrated, one in color. There is a brief index. This book is not likely to interest the general practitioner, but it should be of great value to anyone who deals with mentally retarded children.