This chapter introduces the self-study of practice as a field of research grounded in the systematic investigation of one’s professional work. It defines self-study, traces its philosophical and methodological foundations, and situates it within broader traditions such as narrative inquiry, action research, and practitioner research. The chapter outlines the historical evolution of self-study from its emergence among teacher educators in the 1990s to its establishment as a vibrant international community supported by conferences, journals, and book series. Attention is given to the expanding scope of self-study across disciplines, demonstrating how practitioners use it to theorize and improve their own practice. Readers come to understand self-study not only as a methodology but as a professional stance that unites personal reflection with public accountability.