Borneo, the third largest island in the world, has the largest known amphibian fauna in Sundaland, the portion of the East Indies lying on the continental shelf of Asia. This monograph was the first attempt to summarize knowledge of that rich tropical fauna. It presents full descriptions of all species, including eight described for the first time. It covers taxonomic, ecological, and biogeographical relations of each species, including what was known of the tadpoles of each species. It includes keys to the families, genera within families, and species within genera. Although much has been learned about this rich fauna since the first printing of this monograph, it still represents the most complete treatment of the fauna.