This article is an exercise in historical sociology. It deals with inconsistencies, absences, and unresolved issues in understandings of children's usefulness. Demography, histories of childhood, feminist research on housework and welfare states, time-use studies, psychology, ethnography, and "new sociology of childhood" often use incompatible notions of the productivity of children's time and effort. What does and does not constitute work is also one of the most keenly contested issues between children and adults. Taken together, these debates and skirmishes are at the heart of fundamental social categories. They help constitute the distinction between children and adults, work and learning, self-care and helping others, current and future usefulness, academic excellence and mediocrity, paid and unpaid effort and time, home, school, and workplace, altruistic and commercial exchange. The bulk of the article deals with countries of the North and draws on English-language studies. The concluding section uses material on countries of the South to suggest that the "majority world" might be pioneering new understandings and practices of growing up.This article is an exercise in thinking through some inconsistencies, absences, and unresolved issues in social science understandings of the usefulness or otherwise of children and young people. 1 Above all, it is an exercise in historical sociology. Without attempting a comprehensive coverage of each discipline, I refer to representative historical, quantitative, ethnographic, and psychological studies to