This is the first study of the language and culture of the Korowai, a Papuan community of treehouse dwellers in the rainforest of southern Irian Jaya, Indonesia. The Korowai are a people who have historically been completely isolated from the world around them and have only recently come into contact with outsiders. The authors, who gained access to the tribe in their roles as Christian missionaries, examine the Korowai language and culture in a systematic and integrated way. They sketch the physical, cultural, historical, and linguistic backgrounds of the Korowai community. Also, they fully explicate the language, presenting in fine detail its phonology, morphology, syntax, and kinship terminology--as well as reproducing oral texts that show patterns of grammar, discourse, and culture. This text will be of value to both linguists and anthropologists, not only because it deals with a neglected and threatened society, but also because it does so by viewing (and documenting) the language and culture of that society in a methodical and holistic manner.