Over the past decade, the field of biocultural diversity has arisen as an area of transdisciplinary research concerned with investigating the links between the world's linguistic, cultural, and biological diversity as manifestations of the diversity of life. The impetus for the emergence of this field came from the observation that all three diversities are under threat by some of the same forces and from the perception that loss of diversity at all levels spells dramatic consequences for humanity and the earth. Accordingly, the field of biocultural diversity has developed with both a theoretical and a practical side, the latter focusing on on-the-ground work and policy, as well as with an ethics and human rights component. This review provides some background on the historical antecedents and beginnings of this field and on its philosophical and ethical underpinnings, and then surveys the key literature on biocultural diversity, concentrating on three main aspects: global and regional studies on the links between linguistic, cultural, and biological diversity; the measurement and assessment of biocultural diversity; and the protection and maintenance of biocultural diversity. The review concludes with some considerations about future prospects for this emerging field.