Intellectual disability is usually thought of as a form of internal individual affliction little different from diabetes paralysis or chronic illness. This study the first book-length application of discursive psychology to intellectual disability shows that what we usually understand as being an individual problem is actually an interactional or social product. Through a range of case studies which draw upon ethnomethodological and conversation analytic scholarship the book shows how persons categorized as ''intellectually disabled'' are produced as such in and through their moment-by-moment interaction with care staff and other professionals. Mark Rapley extends and reformulates current work in disability studies and offers a reconceptualisation of intellectual disability as both a professionally ascribed diagnostic category and an accomplished - and contested - social identity. Importantly the book is grounded in data drawn from naturally-occurring rather than professionally orchestrated social interaction.