The present paper provides an overview of the methodological principles that underpin qualitative research and how these principles differ from those of quantitative research. It is intended to set the scene for the following papers that outline two specific approaches to the analysis of qualitative data. Within the tradition of qualitative research there are many different theoretical perspectives, of which these approaches are only two examples, but they need to be set within this broader tradition in order to highlight their specific features. Qualitative and quantitative research differ from each other in far more than their methods and data. They are each based on very different premises about both the nature of the world and the nature of our knowledge of it and how this information is generated. These approaches have implications for all aspects of research strategy, including the assessment of the quality of research findings and their wider utility or application. In relation to the latter, lack of detail in the reporting of qualitative research and small sample sizes has tended to create the impression that the findings of qualitative research have little application outside the particular research setting. While there is need for more rigor in reporting, it needs to be recognized that qualitative research can offer insights and understandings with wider relevance, although these outcomes are of a different type from those provided by quantitative research.