This volume is what the author says it is—a survey of human nature from the zoologic viewpoint. It is an "exposition of human nature without any plans for its improvement."
In Part I—Man in His Biological Aspects—are discussed such matters as factors common to all living things, man's ancestry, development of behavior, instinct, learning and man in his environment.
Part II—Society in Its Biological Aspects—consists of a discussion of the components of social behavior, the components being physiologic activities, instincts, customs and reason. These component parts are also discussed in relation to war, government and religion.
The subject matter, though complex in nature, is simply given and is such that it will be comprehended and enjoyed by the reader, lay or professional.