We are still faced with a large number of issues before our knowledge is complete about primary hyperparathyroidism. Areas for which more information is needed include etiology, fracture incidence, quantification of neuropsychiatric symptomatology, potential involvement of nontraditional aspects, such as the cardiovascular system, and certain subgroups of patients who may be at particular risk, such as perimenopausal women. Moreover, patients have not been monitored long enough without intervention to assess fully the course of skeletal manifestations. Similarly, patients have not been monitored long enough after curative surgery to know to what extent the increase in bone mass persists. We seek greater understanding of the under lying hormonal and cellular mechanisms for the divergent effects of parathyroid hormone on cancellous and cortical bone in the preoperative state and the uniform anabolic effect following successful parathyroid surgery. Finally, the disorder needs continued, close monitoring because it may well be changing again right before our eyes!.