Chapter 14 Case Study Research Patricia A. Duff & Tim Anderson Introduction Case study generally constitutes a qualitative, interpretive approach to understanding the experiences, features, behaviors, and processes of one bounded unit. The essence and value of case study resides in its (typically) holistic and in-depth characterization of individual entities in context, which permits researchers and readers to gain grounded new understandings of issues. Generally, the cases in our field are language learners, teachers, speakers, or writers, but the case can represent other entities, such as a family, a program, a school, or even a country, where particular language practices are salient and the complexities, interactions, and dynamics of the system can be examined within the fullness of the case. Case study research has been used productively in second language (L2) teaching and learning research for many decades, as well as in other areas of applied linguistics, the social sciences, and other fields. One of the most compelling aspects of case study research is that researchers can describe and account for the many factors and contingencies (e.g., social, cultural, political, geographical, temporal, inter- and intra-personal) affecting a single entity. When that entity is a person, moreover, it is possible to gain a nuanced first-hand perspective of the participant’s experiences and what they mean for him or her, in addition to the researchers’ and others’ perspectives on a person’s attributes, behaviors, or performance. The concrete Duff, P. & Anderson, T. (in press). In JD Brown & C. Coombs (Eds.), Cambridge guide to language research. Cambridge, UK: Cambridge University Press.