This chapter links recent Dutch and Belgian research in historical demography to on-going debates and emerging trends in the fi eld at large. It starts with the perennial -but always fascinating -discussion on how to make sense of the demographic transition, an extremely complex subject. The discussion is currently moving to the wild fl uctuations in fertility in the twentieth century, as well as to other changes known as the 'Second Demographic Transition'. Following this, I discuss how historical demographers are making sense of the huge individual variations they uncover in demographic behaviourincluding family composition, religion, social class and locality. One strategy is to compare and thus control for context in comparative research designs. Another is to try to locate 'universal' elements in demographic behaviour, such as transmitted physiological components. Finally, I show how the concept of long-term traditional, macro-regional family systems is being put to use in contemporary research.