Thirty years after André Chervel's innovative article on the history of school subjects, this special issue aims to put into perspective the recent changes and trends in this field of research, which is now characterised by a growing interest in actors, i.e. those who "produce" the disciplines. It seeks to clarify the epistemological and methodological aspects of this evolution, resituating it in the broader field of research on curriculum and teaching content. The introduction thus questions the specificity of French historical scholarship in this research field, compared with the contributions of other disciplinary approaches, in France and abroad. Focusing on French post-elementary and secondary education in the 20th century, the special issue combines disciplinary and curricular perspectives. It seeks to highlight the multiplicity of actors involved in the design and organisation of school subjects or disciplinary fields - from practising teachers to minister’s advisers - as well as their different actions, both individual and collective. It places particular emphasis on the role of teachers in developing curricula and in asserting the legitimacy of their subjects in the school arena.