In Vitamin D: Physiology, Molecular Biology, and Clinical Applications, Second Edition, Volume 1, leading researchers provide a comprehensive, highly readable overview of the biological functions and clinical applications of vitamin D and its metabolites. Presented in a newly affordable softcover format this volume contains Parts IV through VII of the previously published hardcover text. 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 demonstrates the significant role that vitamin D has in maintaining good bone health and the prevention of osteoporosis, an important health problem for adults over the age of fifty. In addition, it 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, Second Edition, Volume 1 is designed and organized not only to be an up-to-date review on the subject, but also to provide medical students, graduate students, health care professionals and even the lay public with a reference source for the most up-to-date information about the vitamin D deficiency pandemic and its clinical implications for health and disease.