This textbook brings together both new and traditional research methods in Human Computer Interaction (HCI). Research methods include interviews and observations, ethnography, grounded theory and analysis of digital traces of behavior. Readers will gain an understanding of the type of knowledge each method provides, its disciplinary roots and how each contributes to understanding users, user behavior and the context of use. The background context, clear explanations and sample exercises make this an ideal textbook for graduate students, as well as a valuable reference for researchers and practitioners.