We developed a computer-based medical history for patients to take in their homes via the Internet. The history is divided into 24 modules— family history, social history, cardiac history, pulmonary history, and the like. So far as possible, it is designed to model the comprehensive, inclusive, general medical history traditionally taken, when time permits, by a primary care doctor seeing a patient for the first time. It contains 232 primary questions asked of all patients about the presence or absence of medical problems. Of these, 215 have the preformatted mutually exclusive responses "Yes," "No," "Uncertain (Don't Know, Maybe)," "Don't understand," and "I'd rather not answer;" 10 have other sets of multiple choices, one response permitted; five have multiple choices with more than one response permitted, and two have numerical responses. In addition, more than 6000 questions, explanations, suggestions, and recommendations are available for presentation, as determined by the patient's responses and the branching logic of the program. These questions are available to explore in detail medical problems elicited by one or more of the primary questions. If for example, a patient responds with "Yes" to the question about chest pain, the program branches to multiple qualifying questions about characteristics of the pain, such as onset, location, quality, severity, relationship to exertion, and course. Once we had completed the interview in preliminary form, we made it available to members of our medical advisory board for their criticisms and suggestions. We then conducted a formal read-aloud assessment in which 10 volunteer patients read each primary question aloud to an investigator in attendance and offered their understanding and general assessment of the questions. We revised our program based on comments from the advisory board and the patients