This thesis addresses academic writing using two practice-led disciplines, academic literacies and ethnomethodology. It is first concerned to evaluate the possibilities of cooperation between these cognate endeavours, and concludes that where academic literacies provides a locus and set of topics for academic writing studies, ethnomethodology can contribute a sharpening of focus and of analytic tools. Ethnomethodology provides a reassuring message in that it confirms the value of detailed local studies, in this case of literacy. However, it is also the source of critique for those literacy scholars who have tried to site their studies in dualisms. This is seen as a rejection of situated studies. There is therefore a prominent methodological focus in this thesis. These methodological issues are then discussed in regard to how they translate into agendas and technologies for the study of social literacies. It is shown that ethnographic-type methods are necessary for such studies, even where they do not qualify as 'full' ethnographies by traditional standards. This study itself took on a quasi-ethnographic or ethnographic-type approach, using a longitudinal method to track the academic writing practices of eight undergraduate students with the aim of ascertaining the social and collaborative ways in which their work is accorded plausibility. Material from the study is presented in the form of interview analysis, and in a series of ethnographic case studies that use a variety of material, including interviews with students and staff, student essays, and various other materials that were accrued throughout the administrative life of the essays. Various methods for achieving or according plausibility, on the part of both students and staff, are discussed and analysed. Although all protagonists involved in essay writing and marking looked for and dealt in conventions wherever possible, the material presented here demonstrates that participants were generally aware of the limits to the possibilities of phenomena, and that there may be cause to locate, challenge, change, and adapt to the things that can acceptably be said and done in essay writing.