Originally published in 1931, this book provides a summary of ideas regarding evolution and heredity as they existed at the time of publication. Intended for the general reader, and as a foundation for students, the text is broad in scope, covering socio-political areas alongside straightforwardly biological topics. Numerous illustrative figures are also included, together with a glossary of key terms. Whilst much of the content is inevitably dated, particularly the conception of social evolution and human heredity, this book will remain of value to anyone with an interest in evolutionary theory and the history of science.