With computerized health information receiving unprecedented government support, a group of health policy scholars analyze the intricate legal, social, and professional implications of the new technology. These essays explore how Health Information Technology (HIT) may alter relationships between physicians and patients, physicians and other providers, and physicians and their home institutions. Patient use of web-based information may undermine the traditional information monopoly that physicians have long enjoyed. New IT systems may increase physicians' legal liability and heighten expectations about transparency. Case studies on kidney transplants and maternity practices reveal the unanticipated effects, positive and negative, of patient uses of the new technology. An independent HIT profession may emerge, bringing another organized interest into the medical arena. Taken together, these investigations cast new light on the challenges and opportunities presented by HIT.