This special issue of "Linguistics and Education" deals with a specific domain of activities related to the management of discipline in classrooms. Matters of authority and discipline have been widely discussed in educational research literature. Yet, only a handful of studies have investigated how matters of discipline and the boundaries of acceptable behaviour are managed and negotiated locally in the interactional activities that constitute the social world of the classroom. This volume addresses the issue of how teachers, and sometimes students, actually deal with the problem of addressing, referring to, and evaluating unauthorized or inappropriate conduct. The focus is on activities through which teachers and students manage expectations concerning the social and moral order of classroom conduct. These are investigated through the detailed analytic lens of conversation analysis. In this introduction we offer a necessarily selective overview of previous work on classroom interaction, present the key principles of conversation analysis, and introduce the contributions included in this volume.