Heritage language (HL) learning and teaching presents particularly difficult challenges. Melding cutting-edge research with innovations in teaching practice, the contributors in this volume provide practical knowledge and tools that introduce new solutions informed by linguistic, sociolinguistic, and educational research on heritage learners. Scholars address new perspectives and orientations on designing HL programs, assessing progress and proficiency, transferring research knowledge into classroom practice, and the essential question of how to define a heritage learner. Articles offer analysis and answers on multiple languages, and the result is a unique and essential text—the only comprehensive guide for heritage language learning based on the latest theory and research with suggestions for the classroom.