The versatile and the ambiguous nature of the homeroom teachers' role, and the gap in knowledge regarding the homeroom teachers' role development process indicated a need to explore this issue within the context of high schools in Israel. The research described in this book drew on theories relating to role identity development, organisational culture, adolescent psychology, teacher education, and teachers' professional development. The research addressed the following question: 'How do homeroom teachers develop into their roles in high schools in Israel?'. The research adopted an inductive research design, using a qualitative ethnographic research approach and employing multiple-methods. Data were collected from homeroom teachers and principals, using a documentary analysis, original semi-structured interviews, questionnaires, and observations, and data triangulation was conducted. Ultimately, the research developed a new construct to describe and explain the role evolution of homeroom teachers, and developed insights regarding the ways to improve their practice. The insights are both theoretical and practical, and can guide teachers, principals, and teacher educators.