"Stories of lives devastated by conflict or disease are all too common across low-income countries. Lack of an arm or leg can be tough anywhere, but for people in poorer parts of the planet, with so much less support and more rickety infrastructure, it is especially challenging. Some are victims of conflict, others were born with congenitall conditions. Many more are injured on roads, the casualty toll soaring in low-income nations even as it plummets in wealthier ones. Every minute, 20 people are seriously injured worldwide in road crashes. In Kenya, half the patients on surgical wards have road injuries. The World Health Organization (WHO) estimates there are about 30 million people like Nhial and Lam who require prosthetic limbs, braces, or other mobility devices. These can be simple to make and inexpensive. As one veteran prosthetist told me, his specialism is among the most instantly gratifying areas of medicine. “A patient comes in on Monday on crutches that leave them unable to carry anything. By Wednesday they are walking on a new leg and on Friday they leave with their life transformed.” Yet more than eight in 10 of those people needing mobility devices do not have them. They take a lot of work and expertise to produce and fit, and the WHO says there is a shortage of 40,000 trained prosthetists in poorer countries. There is also the time and cost to patients, who may have to travel long distances for treatment that can take five days—to assess need, produce a prosthesis and fit it to the residual limb. The result is that unglamorous items such as braces and artificial limbs are among the most-needed devices to assist lives. Yet, as in so many other areas, technology may be hurtling to the rescue, this time in the shape of 3-D printing."