Information management constitutes a major activity of the health care professional. Currently, a number of forces are focusing attention on this function. After many years of development of information systems to support the infrastructure of medicine, greater focus on the needs of physicians and other health care managers and professionals is occurring--to support education, decision making, communication, and many other aspects of professional activity. Medical informatics is the field that concerns itself with the cognitive, information processing, and communication tasks of medical practice, education, and research, including the information science and the technology to support these tasks. An intrinsically interdisciplinary field, medical informatics has a highly applied focus, but also addresses a number of fundamental research problems as well as planning and policy issues. Medical informatics is now emerging as a distinct academic entity. Health care institutions are considering, and a few are making, large-scale commitments to information systems and services that will affect every aspect of their organizations' function. While academic units of medical informatics are presently established at only a few medical institutions in the United States, increasing numbers of schools are considering this activity and many traditional departments are seeking and attracting individuals with medical informatics skills.