"For weeks and weeks people from ethnic minority communities have been wanting to know how they can better protect themselves from coronavirus." [BBC News June 13th 2020]We believe that during Covid-19, ethnic minority communities in the UK, the USA and elsewhere, and all others vulnerable to seasonal Vitamin D deficiency, have been seriously let down by politicians and medical-scientific officialdom. As a result they have been needlessly deprived of extensive biological knowledge that would have protected them against disease and death from a novel virus, for which adequate levels of Vitamin D are essential.We are two retired physicians of similar ages, who together bring a century of experience to many aspects of medical practice and medical education. This includes the endocrinology of vitamin D, the prevention and treatment of serious infections, experience of previous pandemics, and a sadly sceptical view of present medicoscientific politics.During the course of the Covid-19 disaster we both came up against the neglect of first-line immunity provided by adequate levels of Vitamin D, critically important for effective defence against invasion by all new viruses, and supported by science. This is explored from many aspects in this book, in which we identify important lessons for the future, including the folly of relying exclusively on Big-Pharma and the scientists it supports.