The second edition of the Atlas of Osteoporosis is designed to be useful to a broad readership united in their interest in the disorder. The expert authors have encapsulated not only the well-established basics of osteoporosis but also new developments in the field in a format that makes extensive use of graphical displays of important data. Issues that are well known to be important to skeletal biology and osteoporosis (eg, nutrition, exercise, and growth) have been updated. That there is substantive new information in these areas is a testament to the vigor of the field and the pace of its advancement. Some chapters included in the First Edition have been more extensively revised to reflect major developments. Several chapters have been added to highlight the emergence of new fields (genetics) or the expansion of others (bone densitometry and the laboratory evaluation of bone disorders).