Mindfulness practice is becoming used increasingly as a treatment in clinical psychology. However there are problems with the research on mindfulness, and until recently there were no measures of mindfulness. The Literature Review analysed psychologists' conceptualisations of the construct of mindfulness, and compared these with Buddhist understandings. It reviewed recently developed methods of assessment of mindfulness, and concluded that there was need for a state measure of mindfulness, one that specifically included assessment of mindful concentration. The Research Report was concerned with the first stage in the development of a state measure of mindfulness, including mindful concentration. It was concluded that further development needed to be done, to establish adequate reliability and validity. A Critical Appraisal is submitted, exploring difficulties in the process of research and the limitations of the research study.