This paper describes the HERMES project, a multinational macrosectoral European econometric modelling effort, sponsored by the Directorates General II (Economic and Financial Affairs), XII (Science, Research and Development), XVII (Energy) and the SOEC. The set-up of the model is sketched against the background of problems of growth, unemployment, inflation, trade balances, government balances and energy policy. Although the definitions of the variables and a complete specification of the model are given in the Appendix, the major features of the model are described extensively in the text. These include private and collective consumption (incl. a consumer demand system), the putty-clay production process, price and wage formation, sectoral bilateral trade flows and integrated energy economy modelling.