The rationale, development, and implementation of a computer-based reference advisory system (RAS) in public health called Public Health Librarian (PHL) are described. The general purpose of RAS is to provide reference tool suggestions to students in the highly diversified studies of public health in San Diego State University's Graduate School of Public Health. The multidisciplinary nature of public health lends itself to the design of RAS, which brings together key resources across the boundaries of social and medical sciences.