Radiogrammetry, single and dual Photon Absorptiometry, Neutron Activationand C-T Densitometry. Part I of the volume deals with a comparison of the accuracy, precision and choice of site of measurement for the different methods. The papers in the second part discuss how to express the measurements, in absolute or normalized values, and theoretical considerations for the best method to use are outlined. In the third part, the clinical relevance of peripheral, axial and total skeletal mass measurement is presented.