The thesis focuses on the Luxembourgian social policy and law with regard to early childhood education and care for the last 25 years. Young children are not yet obligated to attend school. The care and education of these children takes place in day care centres and in the household of child minders as well as in the private sphere of the parents’ home. Policy shapes the care of young children between parents’ home and day care through law and social rights. Along with that, policy implicitly uses ideas of early childhood and mental constructions of how young children grow up. The re-institutionalisation of early childhood is the central approach to analyse these ideas and constructions. In light of the social, cultural and political developments in Europe, especially concerning transformations of family forms and labour markets as well as welfare state change and restructuring, the mental constructions and ideas of early childhood fundamentally change. They become increasingly embedded in rationales in which the care of young children is oriented towards the labour market and the child care market. The qualitative document analysis examines this nexus with reference to the Luxembourgian social policy and law in three continuous phases. The 1990s are dominated by traditional ideas of ‘the young child in domestic care’ in an intimate relationship with the non-working mother. Around the turn of the century, this idea is overlaid by the idea of ‘the young child of working parents’ who is looked after outside the private sphere. Here, the main political rationales are based, not on the situation of young children, but on the occupational and private circumstances of parents and how to support them by means of child care. In the late 2000s, an entirely new idea of early childhood emerges in social policy and law on young children’s care. For the first time, the law strengthens the independent societal status of children and confers the right of care and education to ‘the legally individualised young child’. Paradoxically, these very different constructions of young children and corresponding ideas of early childhood nowadays pertain simultaneously. Therefore, the diversity and multi-layered nature of ideas shapes the contemporary everyday life of young children in Luxembourg.