With the growing incidence of fragility fractures in Europe and North America over the last three decades, bone loss and osteoporosis have become active areas of research in skeletal biology. Bone loss is associated with aging in both sexes and is accelerated in women with the onset of menopause. However, bone loss is related to a suite of complex and often synergistically related factors including genetics, pathology, nutrition, mechanical usage, and lifestyle. It is not surprising that its incidence and severity vary among populations. Each chapter highlights the multifaceted nature of bone loss and fragility. Several underlying themes are common between the chapters, particularly the value of biocultural an evolutionary perspectives in the study of bone loss and fragility. The contributors come from a variety of fields, and this volume is intended for a diverse audience including physical anthropologists, osteologists, bioengineers, and clinicians in sub-disciplines such as rheumatology, orthopedics, and general medicine.