This study examines elite discourse about crime and criminality in modern Mexico. This discourse was intimately connected to discussions of citizenship (and thus inclusion in the Mexican nation-state) which became increasingly important after Independence from Spain in 1821. Elites recognized that a broad, egalitarian definition of citizenship was a potent source of legitimation for a nation in the throes of self-definition. To these discussions of citizenship, discourse about crime and criminality added an effective counterpoint, identifying individuals and groups within the new nation that merited exclusion. Specifically, this study examines the emerging discourses of criminology and penology which attempted to bring a rational, even scientific approach to the long-standing problem of crime. These "liberal" discourses (and the criminal justice system they inspired) eschewed the overtly racist and classist legal legacy of Mexico's colonial past. However, despite their egalitarian pretensions, criminology and penology often rearticulated colonial social distinctions, first by covertly embedding traditional biases in a contradictory liberal rhetoric and later by legitimizing these prejudices with evolutionary science. Ultimately, little changed in post-Independence Mexican social relations: the poor, the indio, the mestizo continued to be excluded from participation in mainstream society, not because they were legally segregated as in the colonial period but because of their supposed criminality. Even Mexico's great social revolution generated few effective changes. Like their predecessors, revolutionary elites attempted to exploit the legitimizing potential of the criminal justice system but again without significantly redefining its basic clientele. The socially-marginal continued to pose a threat to public order and economic progress; thus they continued to be excluded from public life. Within this larger context, specific chapters also function as independent essays: chapter one examines the racist and classist subtexts embedded in post-Enlightenment, "classic" criminology; chapter two, the role of evolutionary science in legitimizing these subtexts; chapter three, the use of popular literary techniques in the construction of "scientific" criminology; chapter four, the place of prison reform in Mexican political discourse; and chapter five, the role of penal code reform in political legitimation.