This chapter follows the development of Computing Education Research (CER) from how the CER community emerged from investigating teaching computer science (CS) as a tertiary education subject to becoming a research discipline of its own. Given the rapid growth of Computing as a discipline and the complexity of the research foci aligned with the educational transformation, it is clear that a single definition of CER is not possible. However, taking a historical perspective, including the development of a sense of scholarship, allows us to analyze the focus of CER over time. Furthermore, we will provide an environmental structure for CER that includes the components computing in general, learning and teaching computing, and educational research, to discuss the interaction and overlap between CER and the other aspects of the field of Computing. The concept of scholarship gives a common ground for valuing CER. To that end, we provide a short introduction to scholarship based on a framework developed by Glassick et al. (Scholarship assessed: evaluation of the professoriate. Jossey-Bass, San Francisco, 1997) as a basis for the CER community. Finally, we will reflect on the status of CER as a discipline. In this, we will use some criteria from Fensham (Defining an Identity: The Evolution of Science Education as a Field of Research. Springer Science & Business Media, 2004) for a discipline and provide our assessment of how well CER fulfills these criteria. We argue that CER has matured to be seen as a legitimate research discipline and conclude by relating CER to other examples of Discipline Based Education Research (DBER). The chapter lays the groundwork for some of the remaining chapters by presenting our perspective on influential contributions to the international dialogue concerning the content and structure of CER. The chapter also provides an overview of some attempts to define the field, including significant books about CER, panel sessions at major conferences, taxonomies, and structured literature reviews.