The most disturbing aspects of the growth of underground economies are the interrelated problems of unreported and unrecorded income. A large and growing underground economy can thwart fiscal efforts to establish budget balance and may significantly undermine the veracity of a nation's economic information system. The notion that economic information is itself endogenous raises the possibility that at least part of the economic malaise observed in most Western nations during the past two decades is essentially the result of a statistical illusion. The essays in this volume examine the problems of defining, measuring and understanding the implications of the underground economies that have emerged in many of the world's developed nations. Empirical chapters examine the conceptual problems of how to measure a phenomenon that attempts to defy detection. Alternative measurement procedures are evaluated. Specific studies are included for the United States, the Netherlands, the United Kingdom, Germany, Sweden, Italy, Norway, Canada, France, the Soviet Union and Hungary.