The rain forest canopy is a seamless web through which arboreal creatures efficiently move to reach the edible fruits without any atttention to the individual trees.Individual health care computer systems are rich with patient data, but rather than a canopy linking all the trees in the forest, the data "fruit" come from a diverse forest of individual computer "trees"-laboratory systems, word processing systems, pharmacy systems, and the like. These different sources of patient information are difficult or impossible to reach by individual physicians, especially from their offices. The World Wide Web and other standardization technology provide physicians and their institutions the tools needed for seamless and secure access to their patients' data and to medical information, when and where they need it. We and others have adopted these tools to combine independent sources of clinical data. Physicians who assist in the purchase of clinical information systems should demand products in their practice settings that are Web enabled, use standard coding systems, and communicate with other computer systems via broadly accepted protocols.