This thesis is an exploration of the professional knowledge of Early Intervention Parenting Clinicians (EIPCs), social workers and psychologists, with the intention to understand more comprehensively the diversity of knowledge that informs their understanding of parenting. Accordingly, the study aimed to: Gain an understanding of what constitutes the professional knowledge of EIPCs;Identify what impacts on professional knowledge, including the sources of knowledge used;Gain insight into how knowledge is used and subsequently developed for practice.Two research questions guided the study:What impacts on the professional knowledge of EIPCs?How do EIPCs use professional knowledge?The study is premised on the vi ew that there is much m ore to know about the prof essi onal knowledge of practitioners in the human services, and a need to understand how knowledge is being translated and expressed in everyday practice (Payne, 2007;. A gap noted in the literature related to professional knowledge is that it is often discipline specific, which can have implications in understanding professional knowledge when various professions are employed to undertake the same role. Eraut's (1994Eraut's ( , 2007 framework for professional knowledge provides the conceptual lens through which to analyse and understand the findings of the study. Eraut recognises the complexity of prof essi on al kn owl edge i n i ts b roadest sen se, a n d arti cul ates a m odel rel ev an t to a ran ge of professions. Professional knowledge is characterised as including: 'procedural knowledge, propositional knowledge, practical knowledge, tacit knowledge, skills and know-how' (Eraut, 1994, p. 16).The study used a qualitative, multi-method design in order to examine the professional knowledge of twelve EIPCs employed by Queensland Health. Data was collected in two stages. The methods used were, semi-structured interviews, which included concept mapping and use of a vignette, and written practice reflections. The methods aimed to gather participants' views on parenting and the parent-child relationship, asking them to share their understandings and the knowledge informing these understandings. Data was then analysed by inductive and deductive approaches.iii The findings focus on what impacts on the professional knowledge of EIPCs, and how EIPCs use knowledge to inform their understandings of parenting. It was thought at the outset of the study that participants' experience and discipline would have an impact on their professional knowledge, however this was not the case. Context was identified as impacting on knowledge, specifically the organisational, theoretical, and individual and practice contexts. A distinction was noted between participants who gave preference to using an organisationally prescribed approach, as compared to those who sought and adopted broader approaches to knowledge, which included interactions with service users, colleagues, supervisors and personal life experiences.How knowledge is used was influenced by the degree of refl...