This Working Paper explains the utility of combining monetary accounts with biophysical accounts to track progress towards sustainability. Monetary accounts capture information on the assets that contribute to a nation's wealth, on the assumption that safeguarding wealth is indispensable for maintaining economic vitality. Biophysical accounts consider the uses of domestic and global natural capital, on the assumption that maintaining economic vitality depends on basic ecological services such as renewable and non-renewable resources, waste absorption, and stable climate conditions. Used in tandem, these two measurements provide policymakers with detailed intelligence on economic and ecological viability. Such an approach can also illuminate ...