One logical way to teach psychology to beginners would be by showing the development of traits, mental functions and abilities with the increase in age of an individual. The present work is an admirable attempt to do this by showing ontogenically the mental capacity of the human child, the adolescent, and the mature and senescent adult. A well selected synthesis of facts about heredity and embryology, with emphasis on the nervous system, precedes chapters dealing with the infant before speech begins and after its onset. Succeeding chapters describe in chronological order the social, emotional and other characteristics of the mental life of the child through prekindergarten, kindergarten, school child and college student ages. Daily the genetic psychologists of the country are pouring out more experimental results, so that selection of these in such a way as to show how they fit together to form living personalities is no mean task.