 I'm Kunal Sen, the director of UNE Wider, and I'm one of the three editors of the book. The core policy challenge that we have right now in the Estastro-Libu-Delupengol Agenda is inequality. There's been a lot of work on inequality from very different scholarly traditions, but what we don't really know much about is inequality across generations, and that's social mobility, and that's exactly what this book is about. So far the focus has been on making sure that households cross the poverty line. The focus on social mobility goes beyond this because we are lifting the perspective to also ask the question about what happens to those who move above the poverty line. Are these just marginal changes or are there more substantive changes? What I discovered to my horror was that while many people had moved out of poverty, they just moved that much above the poverty line. Why not further up? For us, the editors and the contributors to this book, this is not enough. We're also interested in understanding and trying to measure and document the underpinnings of more substantive progress. Why is social mobility so low in developing countries? I asked young people in high school or college, what do you want to be when you grow up? Young people could not see things like becoming a hedge fund investor, an ace athlete or a professor. All they see are the low paid careers that exist within and around communities like theirs. At the same time, there may be many impediments that are driven by social structure, by inequality across different social groups, by gender, by race, by ethnicity. But if you see the work that's happened in social mobility, we tend to see very little work on developing countries. This book is going to be important both for future research and for future policy about social mobility and inequality reduction. UNEWIDER has had the history of setting the agenda on critical issues in research and policy. This book follows in the same tradition. We want to inspire research that can essentially help us understand this complex issue.