This chapter is based on interviews with fifteen authors whose professional textbooks in English didactics are currently on the reading lists for the five-year teacher education programme in Norway called the lektor programme. The chapter starts by defining the genre of the professional textbook, and reviewing relevant research and terminology, before describing the digital interview and transcription processes. Of the many topics raised in the interviews, the following are highlighted in this chapter: the ways in which authors select their writing and publishing partners; how they address their intended reader; how they relate to perceived conventions about what sort of texts belong in a professional textbook; the reasons why student teachers need textbooks; and the varying emphasis placed on different kinds of knowledge: research, theory, repertoire and contextualisation in relation to the current school curriculum. The chapter ends with a summary of the authors’ predictions for the genre, and a discussion of the role that the national accreditation system, CRISTIN, should, but does not yet, play in ensuring the vitality and quality of textbooks in both English didactics and other professions.