Since 1972 there has been a close contact through their publications between the Netherlands Interuniversity Demographic Institute at The Hague and the Population and Family Study Centre at Brussels. This co-operation has resulted in the joint publication of the journal Bevolking en Gezin (Population and Family) in the Dutch language. However, there has been a need for wider circulation of the Dutch language studies and research in the field of population and the family. In particular it was thought necessary to make possible an exchange of ideas and findings with popUlation and family scientists abroad. The volume Population and Family in the Low Countries intends to facilitate this international discussion by at least partially lifting the language barrier curtain. Some of the articles and documents included were originally published in the Dutch language, others were written especially for this volume. Population and family covers a very wide field and so do the chapters presented. In addition to demographic studies, articles are presented on population and family sociology and social biology. The editors hope that this second volume of Population and Family in the Low Countries reader, the sixth in their yearly publication series, will serve its purpose. The editors v Contents PREFACE V CONTRIBUTORS IX 1. J. GODEFROY A graphic representation of the process of population renewal - a demographic teaching aid … … … … … .