Research on the scientific and technological education of very young pupils has been developing significantly in recent years in France and in other countries. However, this research is still limited compared to that on older pupils. Moreover, the very nature of this early scientific and technological education is not the subject of a consensus (or is still a subject of debate) either at the level of the various institutional prescriptions or at the level of the researchers who are interested in it. Should this education be considered from the point of view of the content of the higher levels, or should the specific characteristics of this school segment be taken into account first and foremost? It is within the framework of the development of this still emerging research problem that the RDST journal has decided to devote the dossier of n°22 to the scientific and technological education of pupils aged 2 to 6. This dossier includes 6 articles presenting various approaches to content relating to the world of matter or objects. Three complementary research perspectives are present in this dossier: pupils' learning, teaching practices and curricular contents. The articles in this dossier provide some answers in these three directions, and also point to questions that are still open.