Extract: For clinicians wanting to keep up to date, the proliferation of research in a impossible blessing. Medline, for example, adds over one million new records each year. Because of this tsunami of new information, it has been estimated, for example, that around 7% of the clinical conclusions form systematic reviews change every year. Without some systematic assistance, keeping abreast of this vast and scattered research literature is simply not feasible for clinicians. As the problem has grown, attempts at systematic assistance to cope with it have evolved in two ways: collected summaries of texts and bibliographic databases, now electronic.