In this chapter, we explore what kinds of research themes on lifelong learning have been salient in a selection of peer-review journals written in the English language throughout the last half-century. We draw on large-scale text mining techniques to identify 15 latent topics that have been the most prevalent within academic journals and trace how the semantic composition has changed in character over time. Based on this topic model analysis of metadata from 4561 articles, we show how the research field of lifelong learning hinge on broad distinctions between education and work, quantitative and qualitative research paradigms, as well as encompassing more fine-grained research clusters within this broader frame. We conclude by arguing that research on lifelong learning has undergone substantial changes since the 1980s, especially with regard to adult education that has lost its former role as the center of gravity with increased attention being directed toward learning within higher education as well as in relation to workplaces.