Building on the foundational work of Horwitz et al., research on foreign language anxiety (FLA) has expanded significantly over the past four decades, generating a substantial body of knowledge across a wide range of subtopics. Core areas of investigation include the measurement of FLA, identification of anxious learners, sources and effects of FLA, skill-specific anxieties, associated factors, anxiety in heritage language learners, and strategies for FLA reduction. This concluding chapter provides a synthesis of key findings related to these central issues, reviews commonly employed research methodologies, discusses practical implications for language teaching and learning, and outlines directions for future research.