"Ester Boserup's writings have had major impact over the last quarter century on the evolution of thought in anthropology, demography, economics, and sociology about the interrelationships among economic, demographic, and technical change." In the present booklet, the author reviews seventy years of work and writing on development economics and its relation to her own experience, from government planner in Denmark during the Second World War, via the UN, to consultant concerning today's problems of the Third World.