This paper reviews half a century of research into the determinants of fertility. It is argued that the quest for the determinants of fertility behaviour and change during that period can best be interpreted as the development of a series of sub-narratives from different disciplinary perspectives and orientations. These are normally based upon the initial narrative of the demographic transition and usually take the form of a verbal theory illustrated by a 'box and arrow' diagram. On occasions formalization has been attempted. Different parts of the initial narrative have been highlighted at different times depending on policy interest, improvements in technical skills, availability of data, changes in social setting, and the degree of satisfaction with the dominant sub-narrative of the day. There is every reason to believe that the research process identified will continue and will lead to a further accumulation of knowledge. In fact, all important variables have probably already been identified. That it will, ultimately, lead to a single, consolidated narrative fully satisfactory for all settings and for all time is, however, highly unlikely.