Nutrient Power is a synthesis of the research and results of Dr William J. Walsh's multi-decade long study of many different diseases and how their underlying causes can be shown to have common nutritional deficiencies. It also outlines many different supplement regimens which can be used to correct those deficiencies and thereby relieve the symptoms of those diseases to varying degrees. In some cases, completely. Though the regimens are necessarily only outlined since they were designed to be administered by doctors after blood testing for the nutritional status of each patient.
Here is a page from the site of Dominic Pukallus (Facebook group moderator) about the book: