This exploratory study is an attempt to provide some evidence relating to the experiences, assumptions, practical knowledge and expertise that teacher educators hold and use. It aspires to present an illuminative view of some of the roles they fulfil, and tries to capture the sorts of knowledge and understandings that underpins their work with student teachers. Five PGCE tutors from the School of Education at the University of Bristol were the key units of analysis. The investigation harnessed a qualitative methodology in order to answer four key research questions: to what extent has the teacher educator's past experience shaped their practical professional knowledge? How and in what ways do they describe their experiences in teacher education? What is the nature and character of the knowledge they hold and use? How do they use their knowledge in the context of their subject work? The five detailed person-in-context case studies and the resulting cross-case thematic analysis reveal the tutors' knowledge to be characterised by seven key themes: intentionality; practicality; subject specificity; ethicality; generativity; efficacy and ambiguity. Furthermore, the investigation shows the knowledge of tutors to be deeply biographical, intensely practical and distinctive in a number of ways. Initially, they bring to their work considerable craft wisdom derived from their time as school teachers; this knowledge is added to by the experience of working in higher education thus creating new forms of knowledge, in particular, knowledge of student teachers as professional learners, knowledge of teacher education pedagogy and knowledge of a wide range of professional contexts. This practical professional knowledge is put to use in the training of teachers in a number of ways: first, they select and provide a range of purposeful activities that enable students to focus on various aspects of practice. Second, these activities are carried out in an environment which is flexible, independent, safe and comfortable. Third, they engage their students in collaborative, carefully focussed, inquiry-oriented tasks aimed at reconceptualising their implicit theories about their subjects, teaching and learning to teach. Fourth, they offer their students the modelling of reasoned practice, substantively in terms of suggestions for practice, and stylistically through their own engagement with the teaching process. Finally, the tutors engage their students in tasks that attempt to transform their knowledge and understanding as well as inculcating professional reflection, practical inquiry and a professional vocabulary. Author's note A number of the chapters in this study are based on previously published work but significantly revised in the light of the writing of this dissertation. They also represent the progressive development of my thinking over a number of years. The introduction and conclusion are partly based on Teacher education: the prime suspect, in The Oxford Review of Education,