Joseph Pomeroy Widney offers a history of the Aryan race, which when this book was published in 1907 was thought a branch of the Indo-European and Caucasian peoples.

The author practiced as a medical doctor, having first gained experience during service in the U.S. Civil War. Over many years he became interested in the ancestry and development of humanity, carrying out research from the existing knowledge of his time. Widney developed a theory that successive generations of individual races developed distinguishing characteristics due to the qualities of the soil in which their food was cultivated, and the climate in which they resided. Much categorization ensues, with the author assigning Aryan groups and subgroups to various regions of the world.

In the modern day, Widney's investigations have been proven incorrect. The advent of genetic science disproved the entire hypothesis of an Aryan race, with human lineage shown to have progressed in a completely different fashion. Nevertheless, this book is an illustrative historic example of how human ancestry and racial development were studied and discussed prior to rigorous scientific experiment and the resulting conclusive evidence and data.