The article discusses the problem of mastering a teaching profession from the perspective of the theory of development through instruction by Elkonin-Davydov. The author details the logic and methods of working with teachers. Mastering of the profession in the context of development through instruction is perceived not as a collection of technical algorythms, but as evolution of the content of the teacher's actions and their interpretation from the point of view of the student as the subject of his own learning.