The dissertation explores the prophetic voice assumed by Margaret Fuller, Florence Nightingale, and Harriet Martineau in their morally charged life writing. The dissertation argues that the life writing of these women represents a largely failed literary project, reflecting anxieties about the proper social role of the woman reformer within the Victorian public sphere. The nonfiction of these women also exhibits formal concerns relating to the limitations of the prophetic voice and the difficulty of sustaining the aspiration toward critical objectivity while elaborating a moral rhetoric of rights sensitive to the plight of women and other marginalized, or disenfranchised Victorian social groups.  At times the literary project of these women is a resounding success, clearly disseminating a normative vision of social justice predicated on the interdependent ideals of self-culture and intersubjective, communicative understanding mediated by sympathy. Accordingly, the dissertation shows the extent to which the women's tradition in popular fiction derived from Austen in particular allowed these women to develop a morally charged activist ethos attentive to everyday life—to the feminine, private sphere—as a site worthy of conscientious reflection and social critique for the woman reformer.  Nevertheless, this body of women's life writing simultaneously displays—at the level of its formal linguistic and rhetorical properties—deep-seated tensions between the dialogical and consensus-forging aspirations of this rhetoric and the tendency of these writers to resort to a monological, or sermonizing voice, which I read as an expression of failure and anxiety over the proper role of the woman reformer within a hierarchical and exclusionary public discourse of reform. In particular, the public discourse of sage writing, which these women adapted, did not allot a space for the feminized, conversational, seemingly 'irrational' voice. Individual chapters highlight the tension between the feminized, or conversational speaking voice and the tendency among these women writers to conform (or show appropriate deference to) prevailing social discourses and established rhetorical modes. The feminized, conversational voice is complex and often strained but overwhelmingly fuels the normative theory of self-culture championed by these women.  The introduction surveys previous scholarly treatments of Fuller, Martineau, and Nightingale and argues for the significance of their gendered contribution to the Anglo-American world of social reform. In chapter one, 'Transcendental Excursions: Margaret Fuller's Summer on the Lakes, in 1843 (1844) and the European Dispatches (1846-50),' I argue that Summer on the Lakes reflects a failed literary project illustrative of Fuller's concern that prevailing cultural narratives stifle the intellectual ambitions of the woman reformer by failing to accommodate her both aesthetically and socially. In both works, Fuller recommends the figure of the cultivated American traveler, or 'Thinking American,' as the antidote to the divisive politics and debates common to modern, liberal society. The 'Thinking American' is at once a model public citizen, discerning cultural critic, and aspiring ethnographer. By translating and disseminating a universalist rhetoric of sympathy and the transcendent virtues of self-culture, the figure of the 'Thinking American' functions crucially as a bridge between both Summer and the Dispatches, and, even more importantly, as a theoretical bridge between the Old and New Worlds.  In chapter two, 'Narratives of the Nile: Florence Nightingale's Letters from Egypt as Sociological Monograph,' I argue that Nightingale's privately printed account of her travels to Egypt and Greece in the winter of 1849-5 dramatizes the tensions between Nightingale's keen sense of herself as a religiously motivated public speaker and the Victorian aspiration toward critical objectivity. Thus while Nightingale can sympathetically inveigh against the assaults to human dignity waged against Egyptian women in their everyday lives, she cannot withstand the sheer force of her own ingrained imperialist assumptions in her attempt to write a religiously inspired ethnography.  In chapter three, 'Man (and woman too) has a soul to unfold: Florence Nightingale's Suggestions for Thought,' I read Nightingale's sprawling religious manuscript (privately printed in 1860) largely as a failed experiment within existing modes of self-expression: namely, with sage discourse, religious rhetoric, the novel, and literary criticism. The frenzied pronouncements and severity of the feminine prophetic speaker in this text—even the very rambling, formless, and private quality of the manuscript as a whole—suggest Nightingale's despair over the ability of the woman reformer to lay claim to a legitimate public rhetoric within a hierarchical economy of linguistic exchanges.  In chapter four, 'Reformist Autobiography: Harriet Martineau's Character Studies of the 'Serious' and 'Earnest,'' I argue that Martineau's Autobiography (1877) reflects a decidedly more positive and self-assured version of the feminine, public voice than that assumed by either Fuller or Nightingale. By grounding her social criticisms and observations in the minute analysis of manners and morals—a critical stance associated with Austen's discerning moral heroines—Martineau cultivates a morally authoritative public voice for the woman reformer in the transatlantic public sphere with enduring literary and social repercussions.  The conclusion argues that the Victorian women's life writing analyzed here anticipates the pragmatic feminist philosophy of Martha Nussbaum, particularly her idea of a basic social minimum as the basis for human flourishing in a wide-ranging international context off-limits to her Victorian predecessors.