This study gives an overview of what has been written until now by Western scholars about the Illegal Economy. The paper shows development of modern economic science in the study of criminal activity, behavior and motivation of criminals. The transformation of existing models and development of methodological principals in the field of criminal study have been shown, including absolute rationality of criminals and econometric models based on factors of social and psychological environment. Applications of economic methods in criminology in conjunction with economic theories are exposed. The transformation of the term «Illegal Economy» is separately analyzed as well in foreign studies. Results obtained can be used as the new methodological foundation of criminal economy studies thanks to interdisciplinary approach. New vision on the problem of criminal economy which has shifted from robbery into transnational criminal flows with the usage of corrupted officials is possible only with regard to philosophical, sociological and psychological approaches specific for the studies of previous years.