The social sciences have traditionally used categories such as race, class, gender, and sexuality as resources for social analysis. One of the distinctive contributions of ethnomethodology and its offspring, including conversation analysis (CA), discursive psychology (DP), and membership categorization analysis (MCA), has been to treat categories themselves as topics of inquiry.

Categories in social interaction synthesizes and builds upon several decades-worth of scholarship in these fields, advancing categorial analysis and demonstrating the power and value of an interaction-centered approach to the study of social categories in action. In the process, its authors accomplish a number of things that are long overdue, and conveniently all in one place.

One of the book’s principal achievements is bringing together several lineages of categorial analysis that collectively trace their ancestry to the work of Harvey Sacks (Reference Sacks1992). Despite their shared origins and affinities, these approaches have developed separately and at times been critical of each other. For example, conversation analysts have alleged that MCA is insufficiently disciplined and rigorous in its approach to categorial analysis (e.g. Schegloff Reference Schegloff2007), and MCA practitioners have countered that conversation analysts have an overly restrictive notion of what such analysis must entail (e.g. Fitzgerald Reference Fitzgerald2012). With impressive erudition, Whitehead and colleagues dispel misunderstandings on all sides of the conversation, highlighting points of agreement and establishing a comprehensive framework for future research. Equally important, in my view, is that they make it easier for proponents of these different approaches to categorial analysis to pinpoint exactly where they disagree. Going forward, they should be able to disagree more constructively, and with a broader range of materials than CA typically addresses—following the example set by Sacks (Reference Sacks1992) in his early lectures, the authors work with a variety of sources, including written texts and even fiction, rather than restricting themselves to audio and video recordings alone. In doing so, they demonstrate that and how the interpretive practices of producers and recipients of texts and other cultural artefacts can be made available for rigorous conversation analytic inspection.

A second contribution of the book is its demonstration that conversation analysis can study the ‘big’ social science research topics, including power, inequality, and identity. One longstanding critique of conversation analysis is that it ignores the larger context of social interaction and is therefore unable to address most of the topics that sociologists and social scientists more generally care about (e.g. Billig Reference Billig1999). That same criticism has also been leveled against ethnomethodology (e.g. Coser Reference Coser1975). Categories in social interaction stands as an extended and extensive refutation of such critiques. Importantly, it doesn’t simply tell us that conversation analysis can study such phenomena as power in interaction; it shows us that it can do so, taking up category use as a key site where dynamics of power and privilege that social scientists typically treat in the abstract play out in real time, turn by turn and move by interactional move.

To cite one significant example, the authors show us when and where P_n adequate category collections—Sacks’ (Reference Sacks1992) term for category collections such as sex and age that can be applied to all members of a population—may become relevant in interaction, and the complex ways they intersect local, setting-based categories, such as occupational roles. In this way, they respecify phenomena of intersectionality in terms of members’ practices for their production, while also broadening them well beyond sociology’s usual focus on race, class, gender, and sexuality: these categories matter greatly, of course, but as the authors show us, they come to matter in myriad contexts where they intersect other locally operative categories that participants may use to advance their respective projects.

A third notable contribution of the book is its integration of the systematics of conversation with a systematics of category use in interaction. In many ways, the book does for the study of categories something analogous to what Sacks, Schegloff, & Jefferson (Reference Sacks, Schegloff and Jefferson1974) did for the study of the basic machinery of conversation: it demonstrates that the use of categories in interaction is not haphazard but artfully and systematically fitted to the particulars of interaction, and in ways that have both context-sensitive and context-free features across such domains as action-formation (chapter 4), person reference and address (chapter 5), turn-taking and speaker selection (chapter 6), sequence organization (chapter 7), management of interactional trouble (chapter 8), and management of knowledge and entitlement (chapter 9). At the same time, the authors refute the notion that conversation analysis cannot say anything about categories that are not specifically mentioned by the participants. Were this true, it would indeed put a major limitation on the ability of CA to answer the ‘big’ questions in sociology. Fortunately, it is possible to ground claims about tacit orientations to categories in terms of the displayed orientations of interactants, a point the authors prove time and again throughout the book. As they point out, explicit references to categories are more the exception than the rule and tend to occur in instances of trouble; as they put it, ‘explicit mentions of [categories] may be evidence of trouble arising from failures to maintain their taken for granted relevance, and/or from the potential intersecting or competing relevance of alternative categories’ (112).

This brings me to a fourth contribution of the book, which is its demonstration of the ongoing moral relevance of categories in the conduct of social life. Like categorial identities, people do not typically invoke moral rules or codes in the course of everyday life, and when they do, it is often because the tacit expectations that pervade our taken-for-granted social reality have been violated in some way (Hollander & Turowetz Reference Hollander and Turowetz2023). Instead, they exhibit awareness of moral matters in more subtle ways, including an orientation to categorial norms, obligations, and rules. In line with Garfinkel’s (Reference Garfinkel1967:35) observation that ‘A society’s members know and encounter the moral order as perceivedly normal courses of action’, the authors show us how members use categories as resources for achieving such perceivedly normal courses of action. Their analysis of moral reasoning on and as the ‘rich surface’ (22) of social interaction also offers a welcome counterpoint to the commonplace tendency among scholars, and the broader public, to search for such reasoning exclusively in people’s heads (Hollander & Turowetz Reference Hollander and Turowetz2023). In this way, they give us a program for future research that both explicates how situations achieve moral meanings and avoids the pitfalls of psychologism.

In sum, Categories in social interaction is a significant and timely contribution to the study of categories in action. The book supplies a valuable synthesis, critical assessment, and novel development of several lines of scholarship, and I anticipate that it will orient the research agenda on social categories for many years to come.