This book provides an overview of ninety key concepts which often trouble those who are new to researching within the social sciences. It covers theories of knowledge, methodologies and methods. Each entry offers a definition of a concept, shows how researchers have used that concept in their research and discusses difficulties that the concept presents. The book supports those undertaking their own social research projects by providing detailed critical commentary on key concepts in a particularly accessible way. In exploring these concepts, a wide range of research reports across many different fields are described. These include not only classic accounts, but also a broad selection of recent studies, some written by new researchers. The book will be useful for higher-education students carrying out projects within social science faculties at the end of their first degree or during a master's programme, though it will also be helpful for those undertaking doctoral research, and some entries have been written with the production of a thesis in mind. This second edition of Research Methods: The Key Concepts provides a more comprehensive and up-to-date coverage, as old entries have been updated and 19 new entries added. It helps new researchers to navigate the changing landscape of social research by recognising a) the changes in the ways researchers are thinking about knowledge and acquiring knowledge, b) the increasing use of digital tools to collect data, and c) the desire many contemporary researchers feel to promote social justice through their research.