This book is about verbal interaction in AIDS counselling sessions at a London teaching hospital. In the first place, then, it is a study about structures of interaction in a social setting called ‘AIDS counselling’. More specifically, it is a study about the particular structures of interaction which arise when such counselling is informed by a certain kind of theoretical thinking, namely the Milan School Family Systems Theory.

The book also seeks to be an application of Conversation Analysis. This by now well-established method of interaction research will here be used in the examination of a specific type of professional–client intercourse: one where the professionals have a strong theoretical consciousness which informs their activity. Therefore, the study reported in this book is also an experiment demonstrating the applicability of Conversation Analysis in the research of theory-based interaction.

This is not a study of AIDS, nor is it about the experiences of people living with AIDS. It is not a study of AIDS counselling in terms of the development and distribution of the counselling services, or in terms of the professionals' understanding about what they should be doing, or in terms of the clients' needs for counselling or their satisfaction with what they have received. Moreover, it is not about Family Systems Theory per se. It is an empirical study about face-to-face interaction.

In the Introduction I wish to give the reader the necessary background information which will make it easier to understand the analysis of actual interactional data to be presented later. Three topics will be introduced: first, AIDS counselling as a newly emerged professional practice will be discussed.