This book explores the development and use of communication strategies (CSs) among language learners in a classroom setting and reviews the history of CS research and the various taxonomies proposed over the years. The main study outlined in the book focuses on 18 first-year students at a Japanese university, examining their use of CSs during classroom activities and in video-recorded discussions with partners. Data collection methods included surveys, student journals, interviews, speaking-test scores, and video recordings, which were meticulously analyzed using conversation analysis transcription methods. In essence, this book closely examines students' development and use of CSs and explores how these strategies impact their interactional competence.