The breadth and spread of corpus-assisted discourse studies (CADS) indicate its usefulness for exploring language use within a social context. However, its theoretical foundations, limitations, and its epistemological implications must be considered so that we can adjust our research designs accordingly. This Element focuses on important meta-level questions around epistemology, while also offering a compact guide to which corpus linguistic tools are available and how they can contribute to finding out more about discourse. This Element will appeal to researchers both new and experienced, both within the CADS community and beyond.