We have a particular interest in the development of interpersonal communication in this issue, and in some of the problems that are seen when the system goes awry. Subtle deficits of communication are far more common among children referred to child psychiatric facilities than is generally appreciated. It is arguable that they are probably detected rather more easily by other children than by clinicians or even parents. Subtle disorders of language, particularly the higher-order features of language such as pragmatics, may contribute to the social difficulties faced by many children presenting to psychiatrists and psychologists. Unfortunately, until very recently we did not have any really good measures for detecting and measuring these subtle disorders, which may have profound consequences for children's behavioural and emotional adjustment, and may also contribute to educational failure.

A common clinical problem is the appropriate diagnosis to apply to a child who presents with a mixture of communicative and social impairments. Diagnostic difficulties are compounded by the lack of suitable assessment tools for evaluating how children use language in relation to a given social context. We refer to this issue as pragmatics. Bishop presents data on a new checklist for detecting pragmatic deficits, which is designed for completion by teachers or other professionals who are in daily contact with the child. Her instrument represents an important development. Careful evaluation of the checklist has shown that it can be rated reliably. Information obtained from it is intended to complement that from more formal language assessments, which are for the most part insensitive to children's pragmatic skill deficits. Bishop argues that diagnostic difficulties in the field of communication deficits are not uncommon, and her assertion will find echoes in the experience of many clinicians.