It is, by now, something of a commonplace to refer to things-in-the world – be they ideas, objects or categories of persons – as ‘socially constructed’. Such a commonplace, indeed, that the very idea of ‘the social construction of x’ (whatever x may be), along with the entire project of what is usually described as ‘social constructionist’ (or often it appears, interchangeably, if inaccurately cf. Jacobson, 2001) ‘postmodern’ scholarship, has been famously parodied (Sokal, 1996) and held up to ridicule as a mere ‘intellectual imposture’ (see Sokal and Bricmont, 1999). This book seeks to retrieve something of the utility of the notion of social construction, by way of a detailed examination of professionalised (and essentialised) understandings of persons described as ‘intellectually disabled’, and the analysis of social interactions between members of the helping professions and ‘intellectually disabled’ persons, wherein professional estimation and management of their (in)capacities and (in)capabilities occurs.