This article traces past trends and current developments in medical computing in the United States. It suggests a link between shifts in emphases in medical computing and in federal government policy toward health care delivery. The development of medical computing was not driven solely by the internal imperatives of science and technology, but by dreams and visions of how computers could revolutionize medicine. Such dreams and visions constitute a mythical charter similar to ideologies and rhetoric used to mobilize support by other computerization movements. This mythical charter influenced development of medical computing by tying computing in medicine to policy goals. This charter also affected historical accounts in medical computing, which are characterized by technological determinism and evidence of cognitive dissonance due to failure to achieve policy goals.