An analysis of energy problems requires a comprehensive presentation of basic statistics in original units such as tonnes of coal and kilowatt hours of electric- ity. This type of presentation is published in Energy Statistics of Non-OECD Countries, the sister volume to this publication. The usefulness of such basic data can be considerably improved by expressing them in a common unit suitable for uses such as estimation of total energy supply, forecasting and the study of sub- stitution and conservation. The energy balance is a presentation of the basic supply and demand data for all fuels in a manner which shows the main fuels to- gether but separately distinguished and expressed in a common energy unit. Both of these characteristics will allow the easy comparison of the contribution each fuel makes to the economy and their interrela- tionships through the conversion of one fuel into another.