This book is interesting and shed some light on the evolution of the nutritional sciences through the mid twentieth century, but on the whole this book is very out of date. It contains some terminology and assertions that are no longer accepted by the scientific community, such as the distinction between "plant proteins" and "meat proteins". Definitely to be read as a historical source on the state of nutritional value when it was published (the late 1960's) rather than an informative overview of currently accepted nutritional science.