The sub-title of this book is a study in nutrition which is exactly what it is about. It dates back to the 30s and 40s yet is more applicable in today's world. Its implications are far-reaching yet the study does not seem to have been replicated; I wonder why? Pottenger's own notes (which are also available) make fascinating reading. This treatise set me on the course to further self-study into nutrition and, as the consequence, today (at the age of 75) I am in remarkably good health and biologically I am told that I look and act 15+ years younger than my chronological age! Additionally, I have two Norfolk terriers who are thriving on Pottenger's recommended diet sometimes known among pet owners as the BARF diet. Amazingly, some vets reject Pottenger's findings as the studies were not conducted under today's scientific criteria but, those who do, are acting out of ignorance. The book is best regarded as a primer on nutrition and its principle is worthy of adopting by anyone interested in good health.