Relative to other affluent countries, the United States devotes disproportionate resources to health care with disappointing results. Complex insurance rules and distorted market signals create massive inefficiencies, frustrated patients, and providers burdened by excessive paperwork. Recognizing these problems, entrepreneurs are increasingly applying information technology to health care equipment, monitoring, treatment, and service delivery, creating a sector known as digital health. These technologies, once embedded and distributed around the country, hold the potential to substantially alter the efficiency and quality of health care through the better generation, processing, and use of information; the reduction of overhead costs; and the empowerment of patients.