When people communicate, they often adapt their interaction styles to one another. For example, they may match each other's behavior, synchronize the timing of behavior, or behave in dissimilar ways. This book examines the numerous ways in which people do this verbally and nonverbally. It reviews theories that try to explain and predict interaction patterns and examines issues involved in conducting this kind of research. It concludes with a new proposed theory, Interaction Adaptation Theory, and considers how different interaction patterns can lead to positive or negative outcomes.