This chapter considers how a number of the main research paradigms are warranted when investigating professional practice. By first setting out an understanding of research, the chapter moves on to consider the shift from the neutrality of epistemological authority of certainty to the ontology of judgement, made in the uncertain flux of practice, and offers reasons to believe that certain actions are more trustworthy in explanation than others. Three main methodological discourses are discussed in the context of practice, and a fourth is proposed: a trans- or post-disciplinary approach to the messy research problems of practice. This approach is grounded in critical realism and seeks to deal with issues of normative social practice in ways that matter to those who are involved: practitioners.