Since the publication of Philippe Ariès' "History of Childhood," the suspicion has arisen that childhood and family do not follow any anthropological constants. But how does the transition from the medieval household to the modern family occur? How do both forms of family incorporate the child and provide the socialization context it needs for its further development? David Klett draws on Niklas Luhmann's social theory to answer these questions and demonstrates that the discovery of the child coincides with a radical restructuring of society that makes this discovery possible. The investigation does not limit itself to historical-sociological analyses but also makes a long-overdue contribution to the system theory of the modern family.