This book is a detailed and comprehensive medium helping students and researchers to understand dual energy x-ray absorptiometry (DXA). Dual-energy x-ray absorptiometry has been identified as the best densitometric technique for evaluating bone mineral density (BMD) in postmenopausal women by World Health Organization (WHO). It has based the definitions of osteopenia and osteoporosis on its results. DXA facilitates accurate diagnosis of osteoporosis, examination of fracture risk and taking care of patients undergoing treatment. Evaluation of BMD at multiple skeletal sites, screening vertebral fracture and body composition, including fat mass and lean soft tissue mass of the whole body and the segments are some of the supplementary features of DXA. This book contains reviews and original studies about DXA and its distinct applications in clinical practice and in medical research in several situations like assessment of morphological asymmetry in athletes, resting energy expenditure, study of dry bones such as the ulna etc.