This book outlines the richness of case study approaches in their contribution to theory. It offers master and doctoral students a systematic overview of how to conduct case study research considering the variety of its approaches. A continuum of theory is outlined in order to clarify the contribution of research designs to theory. Research topics, research questions, and the role of the theoretical and empirical state of the art are discussed. The conceptual framework is displayed as an orientation, guiding the study theoretically as well as methodologically. The core of the book is the investigation into the main approaches of case study research. Exploratory, explanatory, constructivist, and extended case study approaches are outlined and compared. Commonalities and differences in data collection and data analysis within case study research are deepened.