New tests and studies continue to reveal exciting information about the power of vitamin D in maintaining good health and preventing major illnesses. 'Why Does Vitamin D Matter?' not only covers vitamin D basics, but also explores the science of the vitamin D receptor (VDR), the protein that binds to the active metabolite of vitamin D to fulfill biochemical functions, it explains how vitamin D analogs directly activate the VDR. Readers will find this e-book informative, not only from the scientific point of view, but also from the potential applications of the knowledge into one's daily life. Starting with a brief history of vitamin D and VDR research, followed by a detailed scientific report of how vitamin D and VDR work, this e-book goes on to cover epidemiological studies that investigate the outcome of vitamin D deficiency and the effects of vitamin D supplementation. Issues related to vitamin D supplementation are also addressed from different angles. This e-book continues with a comprehensive report on the numerous vitamin D analogs currently on the market or in development to treat various diseases, followed by exploring the possibility of developing this class of compounds for additional indications. This book is suitable for both general readers and scientists involved in vitamin D research or students who are interested in a career in biochemical/medical/nutritional research, especially in the field of vitamin D and the vitamin D receptor.