In 1997, Conservation International held a conservation priority-setting workshop in Irian Jaya, Indonesia, bringing together government agencies and conservation organizations. The Mamberano Lake Basin region was identified as a high priority, and this volume offers a biodiversity assessment for the Yongsu-Cyclops Mountains and the southern portion of the Mamberano Basin, both tropical ecosystems that include well-known fauna such as tree kangaroos, cuscus, cassowaries, and many species of birds.