In recent years, analysts, researchers and environmental policy makers have been faced with a serious shortage of empirical data on environmental phenomena. In fact, the information gathered by various organisations has not yet been systematically classified into a consistent system of accounts. This book presents the results of a joint research effort by the Fondazione Eni Enrico Mattei and Italy’s Central Statistical Office (ISTAT) to design a system of accounts for natural and environmental resources. The resulting environmental accounts can be integrated with the existing system of national accounts, in order to estimate the so-called `green GDP‘ or `net national product‘ (NNP).