The volume offers critical reviews of the most relevant, current SLA theory and research about receptive, productive, complementary, and nonverbal communication skills, as well as willingness to communicate (WTC). Each chapter is formatted to include five major topics about each language skill: (1) major theories, (2) critical reviews of salient/current research, (3) commonly-used data collection and analysis techniques, (4) summary of specific pedagogical implications of pertinent research and theory, and (5) theory and research-driven scenarios/activities that can be used in teaching. A teacher or a researcher can pick any chapter in this volume to learn about the most important language skills (e.g., reading, writing, nonverbal communication), while having access to almost everything they would need.