Expands empirical research on peer collaboration and the potential benefits it may bring to learners. This book highlights the role of peer interaction in the foreign language classroom and offers a broad and nuanced exploration of the different factors and contexts that mediate its effect on target language use and development. The chapters focus on different age and proficiency groups (young learners, adolescents, adults), different instruction and task characteristics (face-to-face and computer-mediated instruction, pre-task instruction, proficiency pairing) and a variety of outcomes (fluency, accuracy, language-related episodes, grammatical knowledge, foreign language anxiety and affect, collaborative patterns and perceptions). Together they highlight the importance of interaction and collaboration among peers in the foreign language classroom to foster learners’ communicative abilities and to maximise language development and affect.