This book explores the linkages between age-related pension expenditures and the fiscal space needed to fund them. The book also discusses the different financing mixes used, and the risk-sharing arrangements in four large Asian countries, China, India, Indonesia, and Japan. This book has several distinguishing characteristics. First, it provides a critical review of the existing modelling techniques to project age-related expenditure. Second, it explores the inter-linkages between age-related expenditure, fiscal space, and financing methods. Third, the case studies of four large Asian economies are instructive for other economies, as they need to design and implement context specific policies to find requisite fiscal space and corresponding financing methods. The book also contains a chapter by the Finance Minister of Indonesia that analyses challenges in implementing social security reform. The book thus links modelling techniques, analysis of age-related expenditures, and the challenges of policymakers in an integrated manner.