Nick Sorensen is Visiting Research Fellow at the School of Education, Bath Spa University, UK.

1. Introduction. Part One: Theoretical and conceptual foundations. 2. Understanding improvisation: a working definition and philosophical assumptions. 3. Understanding expertise and the lexicon of advanced professional practice in teaching. 4. Understanding professionalism and the discourses of advanced professional practice. Part Two: The empirical research: the improvisational nature of teacher expertise. 5. The impact of school culture on the development of advanced professional practice. 6. Teacher perceptions of expertise and improvisation. 7. The improvising teacher as a prototype of advanced professional practice. 8. The social construction of the improvising teacher. Part Three: Implications for practice. 9. Towards a long-term framework for the professional development of the improvising teacher. 10. Afterword: the improvising teacher in the COVID-19 present. List of figures. List of tables. Foreword -Theresa Robbins Dudeck. Preface. Acknowledgements.