This research project addresses the following: how topical talk operates in the organisation and management of MSE interactions; and how topical talk operates in the co-ordination of specific service requests and service provisions. It draws on a corpus of audio-recorded and transcribed interactions between general practitioners and persons seeking general medical services in suburban clinics in Brisbane, Australia. The corpus comprised a total of 67 medical service events (henceforth MSEs), audio-taped with the full informed consent of the participants. Many contemporary medical sociological accounts of the operation of topical talk in MSEs, typified by the work of Mishler (1981, 1984) and Waitzkin (1991), remain anchored to the 'professional dominance' thesis (Freidson 1970a; 1970b), arguing for the fundamental conflict between two perspectives - lay and professional. Topical talk has been formulated as one expression of this conflict in 'doctor-centred' communicative 'styles' (Byrne and Long 1976; Silverman 1987). Within such accounts, familiar interactional patterns in MSEs, including the content and structure of topics, have been theorised as instruments of power and control whereby the dominance of specialised medical knowledge and expertise are established and maintained. Mishler's (1984) characterisation of the conflict between a biomedically oriented 'voice of medicine' used by professional physicians (henceforth GPs) and a 'voice of the lifeworld' used by persons seeking medical services (henceforth Ps) is an expression of the 'professional dominance' thesis. The voices are characterised as attesting to a fundamental, theoretically problematic, asymmetry of power relations between GPs and Ps, thereby reinforcing the ideological status of professionals in general and the medical profession in particular. Further, recommendations regarding correctives to 'professional dominance' centre on advice GPs to attend to the primacy of Ps' talk on their experiences of illnesses rather than apparently 'ignoring' or transforming these topics into biomedical accounts of disease. This research project critiques this formulation of topical talk and the traditional theoretical and empirical bases on which it has drawn. This critique arises from the application of ethnomethodological approaches to the study of MSEs. Such approaches, as outlined in Chapters 2 and 3, are characterised by a number of conceptual and analytic premises: First, particular social structural features of social activities and the institutional contexts within which activities occur should not be assumed to be the primary criteria for judging the import and adequacy of situated action. Second, the parties to situated social events mutually constitute those events in the real world. Third, issues of agency are collaborative situated accomplishments such that the management of everyday social activities is accomplished by the people involved who show one another the rationalities of their actions as they assemble the familiar scenic features of those same institutional events (Garfinkel 1967; Sacks 1992a, 1992b). These assumptions have been applied in ethnomethodological analyses of social action, including the analysis of professional service encounters that have critiqued the 'professional dominance' thesis (Eglin and Wideman 1986; Sharrock 1979). The novelty of this study is the analysis of the operation of topic organisation as a phenomenon of order. This study also draws on recommendations within Ethnomethodology (Hester & Eglin 1997b; Watson 1997) that sequential and categorial organisations are mutually informative in the analysis of the rationality of situated social action. One of the particular contributions of this thesis is that it not only jointly applies both conversation analysis and membership categorisation analysis but also extends this recommendation to the inclusion of topic analysis as was originally provided for by Sacks (1992a , 1992b) and Garfinkel and Sacks (1970). Within this study a model of analysis has been constructed that has enabled the analytical consideration of four dimensions of social organisation: local sequential, extended sequential, topical and categorial organisations. The theoretical and empirical concepts of ethnomethodogical analysis have thus been developed and extended within this project. The central findings of this study are that in institutional service events, the 'service topic' is both significant and consequential, and that persons constitute themselves as bona fide incumbents of the categories GP or P by attending to their actions as topically organised. The local adequacy of any particular interactional move (such as questioning-answering, greetings, the design of a topic proposal, etc) is shown to be referenced to the service topic. This study found no evidence of potential or actual "struggles" between the 'voice of the life-world and the voice of medicine'. Rather, this study finds routine recognition on the part of both Ps and GPs of the centrality of the service topic and, thereby, the service task, and no evidence of orientation to distinctive biographical contributions staged in competition with biomedically relevant service topics. It is found that Ps' biographical references were made in the context of an assembled service topic such that particular service tasks, however conventional, were constituted as both relevant and reasonable as medical goods and service for the specific service recipient and provider. At the most general level, it is concluded that the service topic operates as a phenomenon of order in MSEs where order, as defined by Garfinkel and Weider (1992: 202), refers to all of the rationalities evident in the generic features of institutional events and settings, that is, the situated logic and intelligibility as well as the procedures whereby they are constituted as recognisable social events. The thesis concludes with a discussion of the implications of the findings for the theorisation, policy-making, medical education, and practices of GPs and Ps within MSEs. Overall, the significance of this work for researchers into medical interactions is that the relevance of the service topic and its pervasive organisational consequences need to be considered analytically. A major outcome of this thesis is the establishment of a new order of interest within the study of institutional interactions. The project demonstrates the pervasive consequences of service topics and thus provides a step forward in the study of institutional service interactions and ways of theorising their rationality, a step that extends beyond social structural pre-theorisations of power and domination and also beyond interactional accounts of the primary relevance of turn taking structures.