Abstract
This paper will first explore briefly how the case study fell out of favour as a legitimate research tool, and how case study researchers responded to the critique that case study research lacked internal and external validity. Some case study advocates attempted to meet this critique by using the case to compare different theoretical predictions, dividing the case into subcases, or treating the case as an experiment. A more effective response distinguishes between ‘extensive’ and ‘intensive’ research designs, and critiques the extensive model. The paper then provides a clarification of purpose and a revived emphasis on theory, history, and intervention to develop the case study method. This paper will begin to construct a comprehensive case study methodology independent of the old critiques, and will show the crucial place which case studies must occupy in our craft.