We have recently developed an exoskeleton system which has increased a wearer's strength while decreasing their metabolic cost of walking. We intend to tackle the technological barriers to a practical, affordable exoskeleton technology for civilian applications, particularly to assist patients with neurological or muscular mobility disorders. These powered human exoskeletons would allow their wearers to walk upright without the strain and muscular effort required by today's unpowered orthotic devices. We argue that these "smart exoskeletons" could replace wheelchairs for many patients for hours at a time, enabling patients who cannot now walk to regain a degree of walking mobility, and to retard the onset of a wide range of secondary disabilities associated with the long-term use of wheelchairs. The proposed system would incorporate several innovations, including a compact, on-board power regeneration system to greatly extend on-board battery life, an advanced control system and user interface to tailor the amount of motive assistance provided to the patient's needs, and a non-constraining, lightweight structural design that is easy for patients to put on and take off with minimal assistance. Solving these problems will open up large new international markets in orthotic exoskeletons, greatly improving the medical situation and quality of life for a large number of wheelchair-bound patients. These technologies also could be adapted for practical, affordable exoskeletons for industrial work, saving thousands of workers from costly back injuries.