The methodological approach to Didactics adopted here is grounded in pragmatism. It is action-oriented and emphasizes learning as the transformation of habits as it occurs in educational settings. Four methodological components have been developed to model the didactic situations and support analysis: (1) the empirical method of inquiry, the notions of (2) selective traditions and (3) organizing purposes, and (4) practical epistemology analysis. Together these tools can be employed for planning, assessing and analyzing the choices of teachers’ regarding methods and content of teaching. They have been systematically developed to support teaching and learning in terms of transactions as encountered by teachers in exercising their profession. The units of analysis concern activities and how they are conducive to the purposes of lessons.