The development of teachers’ professional knowledge

<jats:p>Background. This article is the second in the author&amp;rsquo;s three-part series devoted to the analysis of teacher thinking in different research paradigms. Objective. Whereas the first article in this series, published in Cultural-Historical Psychology (No. 1, 2026), examined process&amp;ndash;outcome models of teaching activity and research on pedagogical decision-making, the present article shifts the focus from the study of pedagogical decisions to an analysis of the structure of teachers&amp;rsquo; professional knowledge. Results. The article gives central attention to L. Shulman&amp;rsquo;s concept of pedagogical content knowledge, which describes a type of knowledge specific to the teaching profession and associated with transforming subject content into forms accessible to students&amp;rsquo; understanding. The development of this line of research is considered through integrative, transformative and consensus models of teachers&amp;rsquo; professional knowledge. It is shown that the concept of pedagogical content knowledge made it possible to clarify substantially the specificity of the teaching profession and to describe the distinctive character of the knowledge required for teaching a particular school subject. At the same time, as the research focus shifted from pedagogical action to professional knowledge, the problem of the relationship between such knowledge and real teaching activity was partly lost. Conclusion. The article argues for the need to supplement the concept of pedagogical content knowledge with the notion of psycho-pedagogical content knowledge, which makes it possible to describe not only the teaching of subject content, but also the development of students&amp;rsquo; thinking through the means of a particular school subject.</jats:p>