This volume addresses the role of communicative interaction in driving various dimensions of second language development from the perspective of Vygotskian sociocultural psychology. Emphasizing the dialectical relationship between the external-social world and individual mental functioning, the chapters delve into a wide range of topics illustrating how the social and the individual are united in interaction. Themes include psychological and human mediation, joint action, negotiation for meaning, the role of first language use, embodied and nonverbal behaviors, and interactional competencies. Theoretical discussions and key concepts are reinforced and illustrated with detailed qualitative analyses of interaction in a variety of second language contexts.