Populations in OECD and emerging economies are ageing rapidly, which will have significant macroeconomic impacts, including on public expenditures and tax revenues. The rules and practices that govern fiscal relations among different levels of government, such as their responsibilities for taxation, spending and debt management, have a bearing on economic efficiency and ultimately growth. The consequences of population ageing at subnational government levels are especially intense. Many local governments are vulnerable to the ageing of their populations from a fiscal perspective. The economic and fiscal challenges of an ageing population go beyond intergovernmental boundaries, and they require complex intergovernmental policy responses. This volume brings together cross-country studies of fiscal policy, demographics and spatial productivity, as well as country studies of Brazil, Canada, China and Germany.