RESUMEN
Over the past several years, thousands of networked information resources have become available to individuals and institutions with access to the Internet. Unfortunately, the dizzying array of computing and networking environments often frustrates end users' attempts to navigate the Internet. Librarians have begun to take responsibility not only for instructing users in the use of basic network tools such as file transfer, remote log-in, and electronic mail, but also for answering questions concerning network access and even information system design. The authors show how, by continuing to adapt to this new and volatile environment, health sciences librarians find themselves playing increasingly important roles in shaping the information policies and practices of their institutions. To illustrate these new roles, the authors review the experiences of health sciences librarians at the University of California, Los Angeles, and the University of California, San Diego. These institutions have varying and complex networking environments, and their biomedical libraries have taken lead roles in clarifying and interpreting their particular Internet features.