This chapter discusses the concept of the second demographic transition (SDT) and its relevance for explaining the ongoing changes in family and fertility patterns across Europe. It takes a closer look at the shifts in values and attitudes related to family, reproduction, and children, and their representation in different chapters in this collection. It re-examines the link between the second demographic transition and fertility, highlights its strong positive association with fertility at later childbearing ages, and suggests that the transition does not necessarily lead to sub-replacement fertility levels. Subsequently, it provides an extensive discussion on the progression of the SDT behind the former ‘Iron Curtain.’ To explain some apparent contradictions in this process, it employs a conceptual model of ‘readiness, willingness, and ability’ (RWA) advocated by Lesthaeghe and Vanderhoeft (2001). It also explores the multifaceted nature of the second demographic transition between different social groups, and points out an apparent paradox: whereas lower-educated individuals often embrace values that can be characterised as rather traditional, they also frequently manifest family behaviour associated with the transition, such as non-marital childbearing, high partnership instability, and high prevalence of long-term cohabitation. This suggests that there may be two different pathways of the progression of the second demographic transition. The concluding section points out the role of structural constraints for the diffusion of the transition among disadvantaged social strata, highlights the importance of the ‘gender revolution’ for the SDT trends, and discusses the usefulness of the SDT framework.