Globally we face a serious set of long-term challenges, including climate change, urban growth, demographic change, economic and technological disruption, and growing systemic risk. Urban and regional planning, particularly for the long-term, is crucial to our ability to respond to these challenges. However, in some countries, planning is under-recognised, under-funded, and more often characterised as the problem than the solution. More broadly, we seem to live in an anti-planning age, of short-term policy and declining trust in governments to take action on major issues. How is it that our belief in planning seems to have diminished markedly, just as the necessity of planning has increased equally markedly? Why is planning facing such an uncertain future, when it is critical to a sustainable future? And if we are to reassert planning’s purpose and relevance, how might we do it? The introductory chapter outlines the central questions and themes that are explored in the book.