This article presents a heuristic inquiry into ego boundary development and functioning in aspiring musicians. In their role as communicators in society, challenging and stretching existing boundaries form an integral aspect of the work of artists. This has an impact on ego boundary functioning. The relevance of both aspiring musicians and their mentors understanding psychodynamic processes at work in musical relations is explained, and implications of technological advancements briefly highlighted. The article shows how Alice Miller’s definition of self-esteem – as being based on the authenticity of one’s own feelings and not on the possession of certain qualities – is narrowly related to ego boundary functioning. The processes involved in ego boundary formation, the development of self and the development of musical identity are shown to be closely related, also neurologically, and a mutual interrelationship between self-esteem, identity and the effectiveness of musical communication was discovered. Writers who portray ego boundary thickness as existing along a continuum are referred to, and possible implications for pathology in musicians are briefly highlighted. The article illustrates that great pedagogues have an intuitive grasp of the importance of these concepts; it makes suggestions for future research and highlights the need for developing a measuring instrument.