This document provides an overview of case study research methodology. It defines a case study as an in-depth examination of a subject of study within its real-world context. Case studies use multiple data sources like documents, interviews, observations and can involve single or multiple cases. Key principles of a good case study are the use of multiple data sources for triangulation, a clear timeline of events, and an organized case study database. Good case studies are significant, complete, display sufficient evidence, consider alternative perspectives, and engage fully with the case. Data analysis and interpretation are subjective and influenced by the researcher's experience. Case studies must avoid overgeneralization and fully acknowledge limitations. The report of a case study includes an introduction, literature review