The "discovery of childhood" is a tricky notion because childhood is as much a fact of a biological and psychological nature as a cultural notion that through the centuries has been the object of changing perceptions, definitions, and images. Children barely speak in history; virtually everything we know about them is mediated by adults. Then how to interpret the theme? This introductory paper proposes a triple approach. It examines firstly, and forcibly very roughly, the discovery of the child in social discourse and social practice throughout history. Secondly, it analyses the invention of childhood in scholarly practice, focussing in particular on the influential study by Philippe Arie's. Thirdly, it briefly recalls the interplay between scholarly work and personal commitment with regard to the discovery of the child as an "historical sensation".