The rapid growth of population in an already overcrowded and hungry world is a nightmare that in the minds of many people matches the fear of nuclear warfare, an association that is underlined by the use of the expression ' population explosion.' Most of those who worry about these problems are puzzled and sometimes angered by what seems to them the unreasoning opposition of the Catholic Church to many of the remedies proposed, contraception in particular, but as Fr. McCormack shows in this study he has written specially for the Faith and Fact series, contraception could not even begin to provide an adequate solution to this gigantic problem.