How to link research to practice in TESOL methodology? This textbook arises out of a need that has existed for years: for trained TESOL teachers to understand both qualitative and quantitative research methods. It proposes that mixed methods research (MMR) meets that need by combining the best aspects of both research traditions. Divided into 3 main sections, each chapter illustrates core principles in practice, using case studies of English teaching worldwide. Written specifically for those studying TESOL teaching, this textbook is the first to teach methods and practice in a global context. In linking to the latest developments in the field, it introduces TESOL teachers to MMR in a reflective and accessible manner. It includes guided tasks in each chapter. It presents extracts and summaries of MMR studies from the TESOL literature and recommends further reading. It covers core topics from vocabulary and grammar, to teaching writing, speaking and listening.