The aim of this essay is to study the basic structure where action-research is based on so as to get involved into school practices. There are several trends and orientations. All of them present a conception of education, a curricular design, school practice and didactic methodology.
The critical action-research develops on the model of practical rationality. When this kind of rationality turns into absolute criterion we abandon other ways of reason without which -as we intend to demonstrate- it is impossible for the human being to reach his full growth.
Key words: Research, Education, Practical Reason, Curriculum, Teaching, School.