Beginning as a critique of the empiricism and liberalism of conventional criminological theory and practice, the new criminology drew on the perspectives of Marx and Engels. However, their thought is ambiguous on many issues. The major branches of radical criminology reflect the different interpretations of Marxism. Critical, materialist, and structural versions of radical criminology each take different theoretical positions regarding the nature and meaning of criminal behavior and the nature of the State. The critical version did not provide a convincing understanding either of the origins of criminal behavior or the State's function in the maintenance of capitalism. Materialist accounts seem cogent, although some of the studies from this perspective have ignored the complexity of politics and ideology. Structuralism has been criticized for its virtual dearth of attention to human agency. Radical criminology currently faces new challenges as Western nations experience deepening economic crises. The recent strong movement to the right in national politics supports the somewhat older 'New Realism' of criminal justice theory and practice. Furthermore, the unabashed punitiveness of neoconservatism has much support from the working class. Notes and 16 references are provided. (Author summary modified)