Professor Groos, who agrees with the followers of Weismann, develops the great importance of the child's play as tending to strengthen his inheritance in the acquisition of adaptations to his environment.

The influence of play on character, and its relation to education, are suggestively indicated.

The playful manifestations affecting the child himself and those affecting his relations to others have been carefully classified, and the reader is led from the simpler exercises of the sensory apparatus through a variety of divisions to inner imitations and social play.

The biological, aesthetic, ethical, and pedagogical standpoints receive much attention from the investigator.

While this book is an illuminating contribution to scientific literature, it is of eminently practical value.