Although the domain of topic organization might appear to be an obvious target of early investigations using conversation analytic techniques, research in this area has in fact proceeded slowly and cautiously. The obstacles here are formidable. Not only is topical maintenance and shift an extremely complex and subtle matter, but also, as Jefferson's discussion of “stepwise transition” illustrates, there are no simple or straightforward routes to the examination of topical flow. Thus “topic” may well prove to be among the most complex conversational phenomena to be investigated and, correspondingly, the most recalcitrant to systematic analysis.

Both contributions to the present part on topic organization focus on the phenomenon of topic transition and begin from Sacks's distinction between stepwise topical movement in which one topic flows into another and boundaried topical movement in which the closure of one topic is followed by the initiation of another.

Button and Casey's chapter focuses exclusively on the boundaried form of topic transition. Here they identify a particular type of topicinitiating utterance, prototypical instances of which include “What's new” and “Anything else to report” that invite coparticipants to furnish new topical materials. These topic-initiating utterances, which the authors term “topic initial elicitors, ” usually initiate a three-turn sequence in which a newsworthy event is offered as a possible topic and subsequently “topicalized ” by the initiator of the sequence.