In 1987, the Pacific Southwest Research Station (PSW) of the U.S. Department of Agriculture Forest Service (USFS) chartered a research work unit to examine outdoor recreation in the wildland-urban interface. The new work unit was established to address the needs of the increasingly diverse recreation visitors to national forests. The four forest supervisors in southern California observed that in the past, most recreation visitors were White. However, that percentage was changing with an increase in diverse visitors. In particular, they noted the increasing numbers of Latino visitors. They also observed that the diverse visitors were recreating in different ways compared to White visitors. The supervisors expressed concern that the needs of the diverse visitors may not be being met because the sites were often developed with White visitors in mind, and thought it was beneficial for PSW to provide scientific information about the diverse outdoor recreation visitors who were using USFS lands for outdoor recreation. The research work unit has emphasized applied research in response. We report 16 studies grouped into six major topical headings: international studies, syntheses of studies, management studies, environmental belief studies, communication studies, and measurement studies.