In this book, Volume III of Clinical Endocrinology, the author attempts to summarize current knowledge of calcium and phosphorus metabolism and to show its relationship to disorders of the parathyroid glands, the kidneys, and the bones. For this purpose he has divided the book into five sections. The first covers normal bone physiology and the metabolism of calcium, phosphorus, magnesium, vitamin D, phosphatase, and citrate. The second covers the known functions of parathyroid hormone or parathyroid extract and diseases of the parathyroid glands. The third covers idiopathic hypercalciuria and those conditions (e.g., hypercalcemia in infancy, hypervitaminosis D, sarcoidosis, malignancy) in which there is hypercalcemia not generally attributed to hyperparathyroidism. The fourth covers glomerular insufficiency and a number of conditions (e.g., rickets, osteomalacia, Fanconi syndrome) in which there is found hypocalcemia not attributable to hypoparathyroidism. The fifth covers disorders of calcification (e.g., calcinosis universalis) or of bone formation (e.g., osteoporosis, osteogenesis