This work examines how a uniquely Jesuit ascetic ideal, or will to power over the self and others, developed on the Spanish-American frontier and was represented in Jesuit-authored hagiographies and natural histories in both New Spain and the metropole during the eighteenth century. As missionaries and prolific authors, the Jesuits were crucial to the expansion and representation of the frontiers of New Spain; likewise, the Spanish-American mission frontier was essential to Jesuit subjectivity as a space of meaningful action where the missionary could perform the ideal of ascetic conduct preserved in Christian tradition. Through the performance of this ideal and the production of missionary narratives and natural histories, the Jesuits bridged the ascetic ideal and the inner-worldly exercise of self-discipline and social control that is central to theories of modernity. The idealized representation of the Jesuit subject's conduct not only reaffirmed the order's corporate identity but also actualized a political and cultural hegemony through narratives that served as a medium for establishing value orientations in all strata of Novohispanic society. Originating in the Society's tradition of "Edifying Letters," eighteenth-century Jesuit narratives increasingly turned towards more detailed accounts of individual subjects' lives and reiterated a common narrative structure covering their early childhood, education within the order, work as teachers and finally the fulfillment of their apostolic vocation on the frontier. This phenomenon is observable in the boom of Jesuit-authored missionary hagiographies appearing in New Spain from 1725 until the expulsion of the order in 1767, coinciding with the Society's most embattled period in both New Spain and Europe. The proliferation of works representing individual missionaries' "vidas y virtudes" was accompanied by the differentiation of missionary biography from Jesuit-authored natural histories, which increasingly focused on a secular European reading public. Nevertheless, both genres reflect the enactment of the Jesuit ascetic ideal in distinct value spheres of colonial and European modernity: while the biography of the exemplary missionary responded to the imperatives of social control and the ethical rationalization of the colonial order, Jesuit natural history presupposed an ascetic subject that increasingly pursued knowledge of the natural world as an end in itself.