In the past decade, considerable progress has been made in the development of methods for assessing the skeleton noninvasively so that osteoporosis can be detected early, its progression and response to therapy carefully monitored, or the risk of fracture effectively ascertained. Clinicians can now evaluate the peripheral, central, or entire skeleton as well as the trabecular or cortical bone envelopes with a high degree of accuracy and precision, and they have the capacity to estimate bone strength and propensity to fracture. The purposes of this commentary are to assess the current capabilities of bone densitometry methods as well as recent technical advances in these methods; to review the statistical approaches applied in studies of bone densitometry; to examine methods of expressing longitudinal sensitivity in densitometry; to address the issues of fracture risk prediction with bone densitometry using either single or multisite measurements; and to delineate the criteria for appropriate use of bone densitometry.