With Dr Harry K. Genant's untimely passing, we note the contributions he made to the field of osteoporosis and bone densitometry including the clinical introduction of quantitative computed tomography, bone densitometry systems validations, universal standards for bone measurement, vertebral fracture assessment, and as a mentor and colleague to countless current clinical and research leaders in the field of osteoporosis. His full biographical sketch is included with remembrances by many of his friends and colleagues on how these innovations came about and shaped the field as it is today.