One answer to the question "How Rich are We?" is to compare levels of National Income either across countries or for a single country over time. However, the relevance of this approach depends on how accurately National Income measures the output of goods and services of a country. While it is difficult to measure, the Black Economy represents the output of goods and services that is not generally captured in the National Income Accounts. This article discusses the problems of measuring the size of the Black Economy and speculates on the questions of who is involved and how. The relative importance of Tax Evasion versus Benefit Fraud is discussed.