These five countries monographs, stemming from a regional research project on "Culture and fertility in Southeast Asia", initiated by the Institute of Southeast Asian Studies, aim at bridging a gap in the study of relationship between ethnicity and fertility in the region. Developed on essentially the same lines, each monograph presents in turn the individual country's historical background leading to the present social structure; the patterns of intergroup behaviour; population policies and family planning programmes; the development of the demographic structure; and finally an analysis of available secondary data, using multiple classification analysis, to determine the impact of key variables on fertility patterns. Though each is an entity in itself, the five monographs complement one another and taken together provide a useful background for future research in the field.