In the last several years, reports of patients treated with bisphosphonates (primarily those delivered intravenously) have emerged associating their use with osteonecrosis of the jaw (ONJ). More than a thousand cases of bisphosphonate-associated ONJ have been identified since the first cases were reported in 2001. In these, ONJ rarely occurs "spontaneously"; the vast majority have been associated as a consequence to oral surgical procedures. Although most of the reports of ONJ have occurred in patients following the use of high dose IV therapy for metastatic bone disease, there are also reports of ONJ in patients taking oral bisphosphonates. Since millions of patients take oral bisphosphonates for the treatment of osteoporosis, it is timely to review what is known and needs to be learned about this emerging issue in patient care—to develop a consensus on the definition of ONJ, as well as to explore potential risk factors and pathogenic mechanisms of ONJ and to explore strategies to move research forward. This volumes seeks to improve awareness of the condition and the need for increased screening and improved diagnosis of ONJ. It also explores possible treatment options for ONJ to help guide future areas for research. NOTE: Annals volumes are available for sale as individual books or as a journal. For information on institutional journal subscriptions, please visit http://onlinelibrary.wiley.com/journal/10.1111/(ISSN)1749-6632. ACADEMY MEMBERS: Please contact the New York Academy of Sciences directly to place your order (www.nyas.org). Members of the New York Academy of Science receive full-text access to the Annals online and discounts on print volumes. Please visit http://www.nyas.org/MemberCenter/Join.aspx for more information about becoming a member.