The communication of relevant information is a central element of health care. Key information about health and illness, health information, is used to direct individual and conjoint behaviors toward the accomplishment of health evaluation and maintenance. The need for accurate and timely health information is not limited to health-care professionals, but is a crucial input for all individuals involved in the health-care system. For example, healthcare consumers, providers, and administrators depend on health information to accomplish many of their goals. Consumers depend on relevant health information to monitor their own health, to seek evaluations of health status from experts, and to identify strategies for maintaining optimal levels of health. Health-care providers need information to keep abreast of key advances in health-care knowledge, to interpret clients' complaints in diagnosing health problems, to monitor changes in clients' health conditions, as well as to direct provision of health-care services. Similarly, administrators Correspondence and requests for reprints: Gary L. Kreps, Department of Communication Studies, Northern Illinois University, De Kalb, IL 60115.