This thesis explores the professional practice of two highly accomplished expert teachers, ‘masters’ of classical ballet, with the aim of providing an understanding of their expertise. A qualitative case study methodology was used to illuminate the masters’ knowledge acquisition and teaching practices. Data collection comprised interviews with the masters and a sample of their students, and teaching observations of the masters at work. A metaphoric conceptual framework of a three-act ballet performance has been used to present the thesis. This dance-related metaphor was chosen: firstly, because it keeps the ballet context in focus; secondly, because it allows for the leading roles to be those of the masters, and their students, and; thirdly because it provides a fitting way to highlight key themes that emerged from the data analysis. Furthermore, just as an entire three-act ballet needs to be experienced in order to fully understand its story, so too, all three acts of the thesis ‘performance’ must be read in order to appreciate the complexity and inter-connected nature of the masters’ practice. Part One (The Programme) provides the foundation work of the thesis (introduction, literature review, methodology, and methods). Part Two includes The Performance, with the Prologue presenting biographic narratives for both masters and each of the three acts revealing key dimensions of the masters’ practice. Act One explores their knowledge acquisition, professional philosophies and beliefs. Act Two explores their professional orientations. Act Three illuminates their expertise in action, within the class and rehearsal environment. Important themes include the recognition that, for the masters, learning and teaching develop over a lifetime and are inspired by an immense passion and dedication for ballet and its teaching. Also, a master brings to the art- form his/her own individuality, and creativity, and actively contributes to ballet’s historical continuum through his/her professional legacy of practice. While some of the findings support aspects already described in the literature about expertise, the use of a domain-specific case study establishes this support, and illuminates a new perspective with much needed evidence. A Grand Finale concludes the study, with the development of a prototypical view of the professional practice of a classical ballet master. Such a prototype has the potential to inform researchers of exemplary practice in other art forms, and more importantly, to highlight the essential characteristics of exemplary ballet masters.