In 1997, Conservation International held a conservation priority-setting workshop in Irian Jaya, Indonesia, bringing together government agencies and conservation organizations. The Mamberamo 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 Mamberamo Basin, both tropical ecosystems including well-known fauna such as tree kangaroos, cuscus, cassowaries, and many species of birds.