1 Introduction

The central tenet of CA is that conversation is sequentially organized. Turn-constructional units, and the actions produced with them, are proffered by reference to what came before and affect what comes next. The focus on sequence organization distinguishes CA from other approaches to language and interaction within the social sciences. Whereas linguistics and psychology have largely maintained an exclusive focus on the composition or design of the singular utterance conceptualized as a phrase or sentence, CA views the positioning of an utterance in the ongoing conversation as fundamental to the understanding of its meaning and to the analysis of its significance as an action (Schegloff, 1984b). This view facilitates an understanding of social actions (see Levinson, this volume) produced in social interaction as positioned either to initiate a possible sequence of action or to respond to an already initiated action as part of a sequence. In this chapter, we discuss the basics of sequence organization in social interaction beginning with basic adjacency pairs and then turning to the main forms of sequence expansion: pre-, insert, and post-expansion. We then turn to a discussion of storytelling organization, and finally to other forms of sequential organization that do not involve the classical adjacency-pair format.