Intellectual disability - ranging from what is more commonly described as 'mental retardation' to 'learning difficulties' - is a socially constructed phenomenon that varies in important respects cross-culturally. This collection of original essays examines the classification of people as competent and incompetent in the United States, England, Wales, Greece, Greenland, Uganda, and Belize. The contributors, anthropologists and sociologists, argue that it is time for a new understanding of intellectual disability. In contrast to medical and psychological models, a social model of intellectual disability emphasises the cultural and individual variability of incompetence, the intimate relationship between cultural categories of competence and incompetence, and the role of social interaction and networks in its social construction. This book is a timely and original contribution to ongoing theoretical and policy debates about disability.