Rapid population growth as a central development problem, the proper domain of government in reducing population growth, and effective measures which can be taken to reduce fertility are examined. Rapid population growth puts a brake on development because it exacerbates the difficult choice between higher consumption now and the investment needed to bring higher consumption in the future; threatens what is already a precarious balance between natural resources and people; and creates urban economic and social problems that risk becoming wholly unmangeable. There are appropriate public policies to slow population growth. Two broad justifications for government action are that a government has a duty to society as a whole and that people may have more children than they want or would want had they more information about and access to easier fertility control. Experience has shown that public policy and programs can and do make a difference. The two policies which are essential to reduce fertility are widespread education, especially for women, and easier access to contraception. There is concluding discussion of how the World Bank is playing an active role in helping address the problem of rapid population growth. (RM)