Case study research is valuable because of its contribution to theory. Without reference to theory, case studies provide anecdotal information. In other words, case studies only have value in relationship to currently held understandings and practices. In this article, I discuss key ideas in the conduct of case study research and show how difficult case study research is. Researchers must have superior conceptual skills. They must be able to apply concepts and hypotheses to particular situations, to extract concepts and hypotheses from particular situations, to use evidence to modify working hypotheses and to develop new working hypotheses, to explain how they developed the theory, to write theory clearly, to present the evidence that supports their contention that their theory is viable and credible, and relate the theory they develop to what is already known.