During the last ten years, the diagnostic approach to disorders of bone and mineral metabolism has benefited considerably from the development of radioimmunoassay and competitive protein- binding techniques for measurements of circulating parathyroid hormone, calcitonin, and biologically active vitamin D me- tabolites. Accumulated experiences with radiogrametrical and densinometric methods of quantitating appendicular bone mass now facilitate the detection of changes in bone mineral content heretofore unrecognized by routine roentgenographic vertebral analysis. During this same decade, the diagnosis of metabolic bone disease and the skeletal response to remedial therapeutic ma- neuvers have also been facilitated by the routine application of the bone biopsy. Improvements in tinctorial techniques, stan- dardization in methodology essential for adequate preparation of thin undecalcified specimens, and the incorporation of tetracy- cline bone formation or mineralization "markers" should now herald the "routine" use of this diagnostic procedure. Moreover, the compilation and ready availability of reference morphometric data, spanning the prepubescent years charac- terized by skeletal growth and remodeling and the later senes- cent period during which bone loss normally proceeds in an un- 7 8 FOREWORD relenting fashion, allow adequate differentiation between normal age-sex-related changes in skeletal turnover attendant on skeletal maturation and aging and acquired or inherited de- rangements in bone metabolism.