Designed for graduate students, instructors, and seasoned researchers, this is an essential guide for robust research design and methodology in applied linguistics, covering qualitative, quantitative, and mixed methods research. It adopts a structured approach, starting with the foundational principles of research design, methodology, and data collection and analysis, to writing and interpreting, explaining, and reporting research results, bringing together all the steps and processes of research from start to finish in one single volume in a way that is practical, easy to follow, and easy to understand. Throughout, the emphasis is on the process of research and the application of various research techniques and principles across different areas. These characteristics, coupled with numerous pedagogical features such as key term reviews, visuals, research scenarios, and many discussion and activity questions, make the book an indispensable reference and a valuable textbook for courses in second language and applied linguistics research.