These revised guidelines reflect the many changes that have taken place in the field of lesbian, gay, and bisexual psychology. Existing topics have evolved and the literature also has expanded into new areas of interest for those working with lesbian, gay, and bisexual clients. In addition, the quality of the data sets of studies has improved significantly with advent of population-based research. As a result, these guidelines provide psychologists with (1) a frame of reference for the treatment of lesbian, gay, and bisexual clients; and, (2) basic information and further references in the areas of assessment, intervention, identity, relationships, diversity, education, training, and research.