"Language and Social Interaction" (LSI) refers to both a subject matter and to a multidisciplinary confederation of research communities assembled and housed within the field of communication. This Handbook is intended to provide a scholarly resource about LSI's subject matter and research, as well as to give visibility and definition to this multidisciplinary confederation. It identifies the main subdisciplinary areas that are confederated in LSI and is arranged for different authoritative voices within each of those subfields to provide their respective views on their subfield's central concerns, its research program and main findings, and its present or emergent issues and directions. The five subfields are language pragmatics, conversation analysis, language and social psychology, discourse analysis, and the ethnography of communication. After reading all of the essays, LSI becomes more clearly defined and circumscribed for readers, and richer in the variety and depth of ways the intricacies of language and social interaction are being revealed. As such, this Handbook is intended for scholars, researchers, and graduate students in language and social interaction.