This Inventory is concerned with direct budgetary transfers and tax expenditures that relate to fossil fuels, regardless of their impact or of the purpose for which the measures were first put in place. It has been undertaken as an exercise in transparency, and to inform the international dialogue on fossil-fuel subsidy reform. For each of the 34 OECD countries covered, the Inventory provides a succinct summary of its energy economy, and of the budgetary and tax-related measures provided at the central-government level (and, in the case of federal countries, for selected sub-national units of government) relating to fossil-fuel production or consumption. The transfers associated with these measures are reported for recent years using the Producer Support Estimate (PSE) and Consumer Support Estimate (CSE) as organising frameworks. These frameworks have already been used extensively by the OECD, most notably in respect of agriculture. The Inventory covers a wide range of measures that provide a benefit or preference for a particular activity or a particular product, either in absolute terms or relative to other activities or products, against a specified baseline. Many measures listed in this inventory are relative preferences within a particular country’s tax system rather than absolute support that can be readily compared across countries, and for that reason no national totals are provided.