A new and often controversial theoretical orientation that resonates strongly with wider developments in contemporary philosophy and social theory, the so-called 'ontological turn' is receiving a great deal of attention in anthropology and cognate disciplines at present. This book provides the first anthropological exposition of this recent intellectual development. It traces the roots of the ontological turn in the history of anthropology and elucidates its emergence as a distinct theoretical orientation over the past few decades, showing how it has emerged in the work of Roy Wagner, Marilyn Strathern and Viveiros de Castro, as well a number of younger scholars. Distinguishing this trajectory of thinking from related attempts to put questions of ontology at the heart of anthropological research, the book articulates critically the key methodological and theoretical tenets of the ontological turn, its prime epistemological and political implications, and locates it in the broader intellectual landscape of contemporary social theory.