The aim of the proposed project is to test several hypotheses concerning the interrelationships between fertility and family organization in rural Taiwan during the period 1905 to 1945. These hypotheses are relevant both to general propositions concerning human fertility and to current interest in Taiwan as a case of demographic transition. The project's independent variables are family structure, form of marriage, female adoption, prostitution, age of weaning, sexual attraction, and the costs and benefits of children. The data are drawn from extensive field research conducted since 1957, from Japanese household registers for the period 1905 through 1945, and Japanese land records for the period 1897 to 1945.