This article makes a contribution to understanding informal argumentation by focusing on the discourse of reading groups. Reading groups, an important cultural phenomenon in Britain and other countries, regularly meet in members' houses, in pubs or restaurants, in bookshops, workplaces, schools or prisons to share their experiences of reading literature, usually fiction. Investigating argumentation in reading groups offers an opportunity for obtaining insight into how people debate with one another in self-organized, informal circumstances. The article reports on an empirical study which investigates the nature of argumentation used in evaluation and interpretation of novels read in a variety of groups. Ten groups were chosen on the basis of differences in age, gender composition, sexuality, setting (e.g. prison, school, university medical department) and geographical location in the UK. The article will investigate this focus through novel synergy between a manual qualitative coding software tool (Atlas-ti) and an automated quantitative tool of corpus linguistics (WMatrix), providing insight into patterns of co-occurrence between linguistic form and discoursal function which illuminate argumentation in reading group discourse.