A comprehensive, highly readable overview of the biological functions and clinical applications of vitamin D and its metabolites. Topics range from the most recent recommendations for vitamin D intake to new approaches for the treatment and prevention of vitamin D deficiency and the development of active vitamin D drugs to treat psoriasis and cancer. The book authoritatively reviews the relationship between sunlight exposure, vitamin D, and increased risk of colon and breast cancer; how vitamin D is made in the skin; and the sequence of events that leads to its activation by the kidney. Also examined are the biological functions of 1,25-dihydrovitamin D3 on the intestine and bone, as well as other tissues, such as skin, the immune system, prostate, and breast, and vitamin D's molecular mechanism of action on the cell membrane and nucleus. Vitamin D: Physiology, Molecular Biology, and Clinical Applications will serve as an authoritative day-to-day source for all those health care professionals, internists, dermatologists, house staff, and basic scientists who seek today's clearest understanding of the broad role of vitamin D in human health.