This timely text provides a comprehensive overview of the research methods used by the Generative Second Language Acquisition framework. The authors lay out the history and state of the art in the field, explain the theoretical underpinnings of this work, and offer practical hands-on guidance for developing, conducting and understanding studies related to L2 grammatical competence—using a rich array of techniques and advancing key insights into the rationale and circumstantial pros and cons of each method. With useful features in a consistent chapter structure, including diverse case studies and discussion questions, the book will be an invaluable resource to students and researchers of SLA, applied linguistics, theoretical linguistics, education, and related areas.