This chapter frames five academic essays concerned with 50 years of didactic professionalisation of Nordic teacher education. It is argued that studies of professions have put more stress on structure and function of reforms than on content and offers a complementary approach. It focuses in particular the role of mother tongue education (L1) in four Nordic countries, both as a school subject, an educational discipline, and a research field. An assumption is that research on mother tongue didactics (Norw. morsmålsdidaktikk) as a field has contributed significantly to increased professionalisation. The book’s five contributors are retired L1 teacher educators and researchers. They have had first-hand experience of a significant knowledge development (Norw. kunnskapsutvikling) that has taken place over decades. They have even taken part in a wide range of research and projects that shaped the L1 field and partly teacher education. Further, the chapter suggests that professionalisation can be broken down into intertwined sub-processes such as academisation, didactisation, theoretisation, and textualisation. These and other key concepts are discussed. While the five personal essays are more empirically oriented, this introduction aims to give a theoretical framework and premises for the book as a whole. All chapters are formed as academic essays and apply an approach inspired by Ivor Goodson’s methodology for writing recollecting lifestories academically backed up by historical contextualisation of described events. This chapter thus presents the epistemology and discusses relevant methodologies.